Network Working Group R. Cole Request for Comments: 1932 D. Shur Category: Informational AT&T Bell Laboratories C. Villamizar ANS April 1996 IP over ATM: A Framework Document
Status of this Memo
This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.
Abstract
The discussions of the IP over ATM working group over the last
several years have produced a diverse set of proposals, some of which are no longer under active consideration. A categorization is
provided for the purpose of focusing discussion on the various
proposals for IP over ATM deemed of primary interest by the IP over
ATM working group. The intent of this framework is to help clarify
the differences between proposals and identify common features in
order to promote convergence to a smaller and more mutually
compatible set of standards. In summary, it is hoped that this
document, in classifying ATM approaches and issues will help to focus the IP over ATM working group’s direction.
1. Introduction
The IP over ATM Working Group of the Internet Engineering Task Force (IETF) is chartered to develop standards for routing and forwarding
IP packets over ATM sub-networks. This document provides a
classification/taxonomy of IP over ATM options and issues and then
describes various proposals in these terms.
The remainder of this memorandum is organized as follows:
o Section 2 defines several terms relating to networking and
internetworking.
o Section 3 discusses the parameters for a taxonomy of the
different ATM models under discussion.
o Section 4 discusses the options for low level encapsulation.
Cole, Shur & Villamizar Informational [Page 1]
o Section 5 discusses tradeoffs between connection oriented and
connectionless approaches.
o Section 6 discusses the various means of providing direct
connections across IP subnet boundaries.
o Section 7 discusses the proposal to extend IP routing to better
accommodate direct connections across IP subnet boundaries.
o Section 8 identifies several prominent IP over ATM proposals that
have been discussed within the IP over ATM Working Group and
their relationship to the framework described in this document.
o Section 9 addresses the relationship between the documents
developed in the IP over ATM and related working groups and the
various models discussed.
2. Definitions and Terminology
We define several terms:
A Host or End System: A host delivers/receives IP packets to/from
other systems, but does not relay IP packets.
A Router or Intermediate System: A router delivers/receives IP
packets to/from other systems, and relays IP packets among
systems.
IP Subnet: In an IP subnet, all members of the subnet are able to
transmit packets to all other members of the subnet directly,
without forwarding by intermediate entities. No two subnet
members are considered closer in the IP topology than any other.
From an IP routing and IP forwarding standpoint a subnet is
atomic, though there may be repeaters, hubs, bridges, or switches between the physical interfaces of subnet members.
Bridged IP Subnet: A bridged IP subnet is one in which two or
more physically disjoint media are made to appear as a single IP
subnet. There are two basic types of bridging, media access
control (MAC) level, and proxy ARP (see section 6).
A Broadcast Subnet: A broadcast network supports an arbitrary
number of hosts and routers and additionally is capable of
transmitting a single IP packet to all of these systems.
A Multicast Capable Subnet: A multicast capable subnet supports
a facility to send a packet which reaches a subset of the
destinations on the subnet. Multicast setup may be sender
Cole, Shur & Villamizar Informational [Page 2]
initiated, or leaf initiated. ATM UNI 3.0 [4] and UNI 3.1
support only sender initiated while IP supports leaf initiated
join. UNI 4.0 will support leaf initiated join.
A Non-Broadcast Multiple Access (NBMA) Subnet: An NBMA supports
an arbitrary number of hosts and routers but does not
natively support a convenient multi-destination connectionless
transmission facility, as does a broadcast or multicast capable
subnetwork.
An End-to-End path: An end-to-end path consists of two hosts which
can communicate with one another over an arbitrary number of
routers and subnets.
An internetwork: An internetwork (small "i") is the concatenation
of networks, often of various different media and lower level
encapsulations, to form an integrated larger network supporting
communication between any of the hosts on any of the component
networks. The Internet (big "I") is a specific well known
global concatenation of (over 40,000 at the time of writing)
component networks.
IP forwarding: IP forwarding is the process of receiving a packet
and using a very low overhead decision process determining how
to handle the packet. The packet may be delivered locally
(for example, management traffic) or forwarded externally. For
traffic that is forwarded externally, the IP forwarding process
also determines which interface the packet should be sent out on, and if necessary, either removes one media layer encapsulation
and replaces it with another, or modifies certain fields in the
media layer encapsulation.
IP routing: IP routing is the exchange of information that takes
place in order to have available the information necessary to
make a correct IP forwarding decision.
IP address resolution: A quasi-static mapping exists between IP
address on the local IP subnet and media address on the local
subnet. This mapping is known as IP address resolution.
An address resolution protocol (ARP) is a protocol supporting
address resolution.
In order to support end-to-end connectivity, two techniques are used. One involves allowing direct connectivity across classic IP subnet
boundaries supported by certain NBMA media, which includes ATM. The other involves IP routing and IP forwarding. In essence, the former technique is extending IP address resolution beyond the boundaries of the IP subnet, while the latter is interconnecting IP subnets.
Cole, Shur & Villamizar Informational [Page 3]
Large internetworks, and in particular the Internet, are unlikely to be composed of a single media, or a star topology, with a single
media at the center. Within a large network supporting a common
media, typically any large NBMA such as ATM, IP routing and IP
forwarding must always be accommodated if the internetwork is larger than the NBMA, particularly if there are multiple points of
interconnection with the NBMA and/or redundant, diverse
interconnections.
Routing information exchange in a very large internetwork can be
quite dynamic due to the high probability that some network elements are changing state. The address resolution space consumption and
resource consumption due to state change, or maintenance of state
information is rarely a problem in classic IP subnets. It can become a problem in large bridged networks or in proposals that attempt to
extend address resolution beyond the IP subnet. Scaling properties
of address resolution and routing proposals, with respect to state
information and state change, must be considered.
3. Parameters Common to IP Over ATM Proposals
In some discussion of IP over ATM distinctions have made between
local area networks (LANs), and wide area networks (WANs) that do not necessarily hold. The distinction between a LAN, MAN and WAN is a
matter of geographic dispersion. Geographic dispersion affects
performance due to increased propagation delay.
LANs are used for network interconnections at the the major Internet traffic interconnect sites. Such LANs have multiple administrative
authorities, currently exclusively support routers providing transit to multihomed internets, currently rely on PVCs and static address
resolution, and rely heavily on IP routing. Such a configuration
differs from the typical LANs used to interconnect computers in
corporate or campus environments, and emphasizes the point that prior characterization of LANs do not necessarily hold. Similarly, WANs
such as those under consideration by numerous large IP providers, do not conform to prior characterizations of ATM WANs in that they have a single administrative authority and a small number of nodes
aggregating large flows of traffic onto single PVCs and rely on IP
routers to avoid forming congestion bottlenecks within ATM.
The following characteristics of the IP over ATM internetwork may be independent of geographic dispersion (LAN, MAN, or WAN).
o The size of the IP over ATM internetwork (number of nodes).
o The size of ATM IP subnets (LIS) in the ATM Internetwork.
Cole, Shur & Villamizar Informational [Page 4]
o Single IP subnet vs multiple IP subnet ATM internetworks.
o Single or multiple administrative authority.
o Presence of routers providing transit to multihomed internets.
o The presence or absence of dynamic address resolution.
o The presence or absence of an IP routing protocol.
IP over ATM should therefore be characterized by:
o Encapsulations below the IP level.
o Degree to which a connection oriented lower level is available
and utilized.
o Type of address resolution at the IP subnet level (static or
dynamic).
o Degree to which address resolution is extended beyond the IP
subnet boundary.
o The type of routing (if any) supported above the IP level.
ATM-specific attributes of particular importance include:
o The different types of services provided by the ATM Adaptation
Layers (AAL). These specify the Quality-of-Service, the
connection-mode, etc. The models discussed within this document
assume an underlying connection-oriented service.
o The type of virtual circuits used, i.e., PVCs versus SVCs. The
PVC environment requires the use of either static tables for
ATM-to-IP address mapping or the use of inverse ARP, while the
SVC environment requires ARP functionality to be provided.
o The type of support for multicast services. If point-to-point
services only are available, then a server for IP multicast is
required. If point-to-multipoint services are available, then
IP multicast can be supported via meshes of point-to-multipoint
connections (although use of a server may be necessary due to
limits on the number of multipoint VCs able to be supported or to
maintain the leaf initiated join semantics).
o The presence of logical link identifiers (VPI/VCIs) and the
various information element (IE) encodings within the ATM SVC
signaling specification, i.e., the ATM Forum UNI version 3.1.
Cole, Shur & Villamizar Informational [Page 5]
This allows a VC originator to specify a range of "layer"
entities as the destination "AAL User". The AAL specifications
do not prohibit any particular "layer X" from attaching
directly to a local AAL service. Taken together these points
imply a range of methods for encapsulation of upper layer
protocols over ATM. For example, while LLC/SNAP encapsulation is
one approach (the default), it is also possible to bind virtual
circuits to higher level entities in the TCP/IP protocol stack.
Some examples of the latter are single VC per protocol binding,
TULIP, and TUNIC, discussed further in Section 4.
o The number and type of ATM administrative domains/networks, and
type of addressing used within an administrative domain/network.
In particular, in the single domain/network case, all attached
systems may be safely assumed to be using a single common
addressing format, while in the multiple domain case, attached
stations may not all be using the same common format,
with corresponding implications on address resolution. (See
Appendix A for a discussion of some of the issues that arise
when multiple ATM address formats are used in the same logical
IP subnet (LIS).) Also security/authentication is much more of a
concern in the multiple domain case.
IP over ATM proposals do not universally accept that IP routing over an ATM network is required. Certain proposals rely on the following assumptions:
o The widespread deployment of ATM within premises-based networks,
private wide-area networks and public networks, and
o The definition of interfaces, signaling and routing protocols
among private ATM networks.
The above assumptions amount to ubiquitous deployment of a seamless
ATM fabric which serves as the hub of a star topology around which
all other media is attached. There has been a great deal of
discussion over when, if ever, this will be a realistic assumption
for very large internetworks, such as the Internet. Advocates of
such approaches point out that even if these are not relevant to very large internetworks such as the Internet, there may be a place for
such models in smaller internetworks, such as corporate networks.
The NHRP protocol (Section 8.2), not necessarily specific to ATM,
would be particularly appropriate for the case of ubiquitous ATM
deployment. NHRP supports the establishment of direct connections
across IP subnets in the ATM domain. The use of NHRP does not
require ubiquitous ATM deployment, but currently imposes topology
constraints to avoid routing loops (see Section 7). Section 8.2 Cole, Shur & Villamizar Informational [Page 6]
describes NHRP in greater detail.
The Peer Model assumes that internetwork layer addresses can be
mapped onto ATM addresses and vice versa, and that reachability
information between ATM routing and internetwork layer routing can be exchanged. This approach has limited applicability unless ubiquitous deployment of ATM holds. The peer model is described in Section 8.4. The Integrated Model proposes a routing solution supporting an
exchange of routing information between ATM routing and higher level routing. This provides timely external routing information within
the ATM routing and provides transit of external routing information through the ATM routing between external routing domains. Such
proposals may better support a possibly lengthy transition during
which assumptions of ubiquitous ATM access do not hold. The
Integrated Model is described in Section 8.5.
The Multiprotocol over ATM (MPOA) Sub-Working Group was formed by the ATM Forum to provide multiprotocol support over ATM. The MPOA effort is at an early stage at the time of this writing. An MPOA baseline
document has been drafted, which provides terminology for further
discussion of the architecture. This document is available from the FTP server https://www.doczj.com/doc/e910461453.html, in pub/contributions as the file atm95-
0824.ps or atm95-0824.txt.
4. Encapsulations and Lower Layer Identification
Data encapsulation, and the identification of VC endpoints,
constitute two important issues that are somewhat orthogonal to the
issues of network topology and routing. The relationship between
these two issues is also a potential sources of confusion. In
conventional LAN technologies the ’encapsulation’ wrapped around a
packet of data typically defines the (de)multiplexing path within
source and destination nodes (e.g. the Ethertype field of an
Ethernet packet). Choice of the protocol endpoint within the
packet’s destination node is essentially carried ’in-band’.
As the multiplexing is pushed towards ATM and away from LLC/SNAP
mechanism, a greater burden will be placed upon the call setup and
teardown capacity of the ATM network. This may result in some
questions being raised regarding the scalability of these lower level multiplexing options.
With the ATM Forum UNI version 3.1 service the choice of endpoint
within a destination node is made ’out of band’ - during the Call
Setup phase. This is quite independent of any in-band encapsulation mechanisms that may be in use. The B-LLI Information Element allows Layer 2 or Layer 3 entities to be specified as a VC’s endpoint. When Cole, Shur & Villamizar Informational [Page 7]
faced with an incoming SETUP message the Called Party will search
locally for an AAL User that claims to provide the service of the
layer specified in the B-LLI. If one is found then the VC will be
accepted (assuming other conditions such as QoS requirements are also met).
An obvious approach for IP environments is to simply specify the
Internet Protocol layer as the VCs endpoint, and place IP packets
into AAL--SDUs for transmission. This is termed ’VC multiplexing’ or ’Null Encapsulation’, because it involves terminating a VC (through
an AAL instance) directly on a layer 3 endpoint. However, this
approach has limitations in environments that need to support
multiple layer 3 protocols between the same two ATM level endpoints. Each pair of layer 3 protocol entities that wish to exchange packets require their own VC.
Cole, Shur & Villamizar Informational [Page 8]
RFC-1483 [6] notes that VC multiplexing is possible, but focuses on
describing an alternative termed ’LLC/SNAP Encapsulation’. This
allows any set of protocols that may be uniquely identified by an
LLC/SNAP header to be multiplexed onto a single VC. Figure 1 shows
how this works for IP packets - the first 3 bytes indicate that the
payload is a Routed Non-ISO PDU, and the Organizationally Unique
Identifier (OUI) of 0x00-00-00 indicates that the Protocol Identifier (PID) is derived from the EtherType associated with IP packets
(0x800). ARP packets are multiplexed onto a VC by using a PID of
0x806 instead of 0x800.
.---------------.
: :
: IP Packet :
: :
---------------
: :
: :
8 byte header V V
.-------------.-------------.------------.---------------.
: : : : :
: : : : Encapsulated :
: 0xAA-AA-03 : 0x00-00-00 : 0x08-00 : Payload :
: : : : :
-------------^-------------^------------^---------------
: : : :
: (LLC) (OUI) (PID) : : :
V V V V
.----------------------------------------------------------.
: :
: AAL SDU :
: :
----------------------------------------------------------
Figure 1: IP packet encapsulated in an AAL5 SDU
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.----------. .----------. .---------. .----------.
: : : : : : : :
: IP : : ARP : :AppleTalk: : etc... :
: : : : : : : :
---------- ---------- --------- ----------
^ : ^ : ^ : ^ :
: : : : : : : :
: V : V : V : V
.-----------------------------------------------------------.
: :
: 0x800 0x806 0x809 other :
: :
: Instance of layer using LLC/SNAP header to :
: perform multiplexing/demultiplexing :
: :
-----------------------------------------------------------
^ :
: :
: V
.------------------.
: :
: Instance of AAL5 :
: terminating :
: one VCC :
: :
------------------
Figure 2: LLC/SNAP encapsulation allows more than just
IP or ARP per VC.
Whatever layer terminates a VC carrying LLC/SNAP encapsulated traffic must know how to parse the AAL--SDUs in order to retrieve the
packets. The recently approved signalling standards for IP over ATM are more explicit, noting that the default SETUP message used to
establish IP over ATM VCs must carry a B-LLI specifying an ISO 8802/2 Layer 2 (LLC) entity as each VCs endpoint. More significantly, there is no information carried within the SETUP message about the identity of the layer 3 protocol that originated the request - until the
packets begin arriving the terminating LLC entity cannot know which
one or more higher layers are packet destinations.
Taken together, this means that hosts require a protocol entity to
register with the host’s local UNI 3.1 management layer as being an
LLC entity, and this same entity must know how to handle and generate LLC/SNAP encapsulated packets. The LLC entity will also require
mechanisms for attaching to higher layer protocols such as IP and
ARP. Figure 2 attempts to show this, and also highlights the fact
that such an LLC entity might support many more than just IP and ARP. Cole, Shur & Villamizar Informational [Page 10]
In fact the combination of RFC 1483 LLC/SNAP encapsulation, LLC
entities terminating VCs, and suitable choice of LLC/SNAP values, can go a long way towards providing an integrated approach to building
multiprotocol networks over ATM.
The processes of actually establishing AAL Users, and identifying
them to the local UNI 3.1 management layers, are still undefined and are likely to be very dependent on operating system environments.
Two encapsulations have been discussed within the IP over ATM working group which differ from those given in RFC-1483 [6]. These have the characteristic of largely or totally eliminating IP header overhead. These models were discussed in the July 1993 IETF meeting in
Amsterdam, but have not been fully defined by the working group.
TULIP and TUNIC assume single hop reachability between IP entities.
Following name resolution, address resolution, and SVC signaling, an implicit binding is established between entities in the two hosts.
In this case full IP headers (and in particular source and
destination addresses) are not required in each data packet.
o The first model is "TCP and UDP over Lightweight IP" (TULIP)
in which only the IP protocol field is carried in each packet,
everything else being bound at call set-up time. In this
case the implicit binding is between the IP entities in each
host. Since there is no further routing problem once the binding
is established, since AAL5 can indicate packet size, since
fragmentation cannot occur, and since ATM signaling will handle
exception conditions, the absence of all other IP header fields
and of ICMP should not be an issue. Entry to TULIP mode would
occur as the last stage in SVC signaling, by a simple extension
to the encapsulation negotiation described in RFC-1755 [10].
TULIP changes nothing in the abstract architecture of the IP
model, since each host or router still has an IP address which is
resolved to an ATM address. It simply uses the point-to-point
property of VCs to allow the elimination of some per-packet
overhead. The use of TULIP could in principle be negotiated on a
per-SVC basis or configured on a per-PVC basis.
o The second model is "TCP and UDP over a Nonexistent IP
Connection" (TUNIC). In this case no network-layer information
is carried in each packet, everything being bound at virtual
circuit set-up time. The implicit binding is between two
applications using either TCP or UDP directly over AAL5 on a
dedicated VC. If this can be achieved, the IP protocol field has
no useful dynamic function. However, in order to achieve binding
between two applications, the use of a well-known port number
Cole, Shur & Villamizar Informational [Page 11]
in classical IP or in TULIP mode may be necessary during call
set-up. This is a subject for further study and would require
significant extensions to the use of SVC signaling described in
RFC-1755 [10].
Encapsulation In setup message Demultiplexing
-------------+--------------------------+------------------------
SNAP/LLC _ nothing _ source and destination
_ _ address, protocol
_ _ family, protocol, ports
_ _
NULL encaps _ protocol family _ source and destination
_ _ address, protocol, ports
_ _
TULIP _ source and destination _ protocol, ports
_ address, protocol family _
_ _
TUNIC - A _ source and destination _ ports
_ address, protocol family _
_ protocol _
_ _
TUNIC - B _ source and destination _ nothing
_ address, protocol family _
_ protocol, ports _
Table 1: Summary of Encapsulation Types
TULIP/TUNIC can be presented as being on one end of a continuum opposite the SNAP/LLC encapsulation, with various forms of null encapsulation somewhere in the middle. The continuum is simply a matter of how much
is moved from in-stream demultiplexing to call setup demultiplexing.
The various encapsulation types are presented in Table 1.
Encapsulations such as TULIP and TUNIC make assumptions with regard to the desirability to support connection oriented flow. The tradeoffs between connection oriented and connectionless are discussed in Section 5.
Cole, Shur & Villamizar Informational [Page 12]
5. Connection Oriented and Connectionless Tradeoffs
The connection oriented and connectionless approaches each offer advantages and disadvantages. In the past, strong advocates of pure connection oriented and pure connectionless architectures have argued intensely. IP over ATM does not need to be purely connectionless or purely connection oriented.
APPLICATION Pure Connection Oriented Approach
----------------+-------------------------------------------------
General _ Always set up a VC
_
Short Duration _ Set up a VC. Either hold the packet during VC
UDP (DNS) _ setup or drop it and await a retransmission.
_ Teardown on a timer basis.
_
Short Duration _ Set up a VC. Either hold packet(s) during VC
TCP (SMTP) _ setup or drop them and await retransmission.
_ Teardown on detection of FIN-ACK or on a timer
_ basis.
_
Elastic (TCP) _ Set up a VC same as above. No clear method to
Bulk Transfer _ set QoS parameters has emerged.
_
Real Time _ Set up a VC. QoS parameters are assumed to
(audio, video) _ precede traffic in RSVP or be carried in some
_ form within the traffic itself.
Table 2: Connection Oriented vs. Connectionless - a) a pure
connection oriented approach
ATM with basic AAL 5 service is connection oriented. The IP layer
above ATM is connectionless. On top of IP much of the traffic is supported by TCP, a reliable end-to-end connection oriented protocol.
A fundamental question is to what degree is it beneficial to map
different flows above IP into separate connections below IP. There is
a broad spectrum of opinion on this.
As stated in section 4, at one end of the spectrum, IP would remain highly connectionless and set up single VCs between routers which are adjacent on an IP subnet and for which there was active traffic flow.
All traffic between the such routers would be multiplexed on a single ATM VC. At the other end of the spectrum, a separate ATM VC would be created for each identifiable flow. For every unique TCP or UDP
address and port pair encountered a new VC would be required. Part of the intensity of early arguments has been over failure to recognize
that there is a middle ground.
Cole, Shur & Villamizar Informational [Page 13]
ATM offers QoS and traffic management capabilities that are well
suited for certain types of services. It may be advantageous to use separate ATM VC for such services. Other IP services such as DNS, are
ill suited for connection oriented delivery, due to their normal very short duration (typically one packet in each direction). Short
duration transactions, even many using TCP, may also be poorly suited
for a connection oriented model due to setup and state overhead. ATM QoS and traffic management capabilities may be poorly suited for
elastic traffic.
APPLICATION Middle Ground
----------------+-------------------------------------------------
General _ Use RSVP or other indication which clearly
_ indicate a VC is needed and what QoS parameters
_ are appropriate.
_
Short Duration _ Forward hop by hop. RSVP is unlikely to precede
UDP (DNS) _ this type of traffic.
_
Short Duration _ Forward hop by hop unless RSVP indicates
TCP (SMTP) _ otherwise. RSVP is unlikely to precede this
_ type of traffic.
_
Elastic (TCP) _ By default hop by hop forwarding is used.
Bulk Transfer _ However, RSVP information, local configuration
_ about TCP port number usage, or a locally
_ implemented method for passing QoS information
_ from the application to the IP/ATM driver may
_ allow/suggest the establishment of direct VCs.
_
Real Time _ Forward hop by hop unless RSVP indicates
(audio, video) _ otherwise. RSVP will indicate QoS requirements.
_ It is assumed RSVP will generally be used for
_ this case. A local decision can be made as to
_ whether the QoS is better served by a separate
_ VC.
Table 3: Connection Oriented vs. Connectionless - b) a middle ground
approach
Cole, Shur & Villamizar Informational [Page 14]
APPLICATION Pure Connectionless Approach
----------------+-------------------------------------------------
General _ Always forward hop by hop. Use queueing
_ algorithms implemented at the IP layer to
_ support reservations such as those specified by
_ RSVP.
_
Short Duration _ Forward hop by hop.
UDP (DNS) _
_
Short Duration _ Forward hop by hop.
TCP (SMTP) _
_
Elastic (TCP) _ Forward hop by hop. Assume ability of TCP to
Bulk Transfer _ share bandwidth (within a VBR VC) works as well
_ or better than ATM traffic management.
_
Real Time _ Forward hop by hop. Assume that queueing
(audio, video) _ algorithms at the IP level can be designed to
_ work with sufficiently good performance
_ (e.g., due to support for predictive
_ reservation).
Table 4: Connection Oriented vs. Connectionless - c) a pure
connectionless approach
Work in progress is addressing how QoS requirements might be
expressed and how the local decisions might be made as to whether
those requirements are best and/or most cost effectively accomplished using ATM or IP capabilities. Table 2, Table 3, and Table 4 describe typical treatment of various types of traffic using a pure connection oriented approach, middle ground approach, and pure connectionless
approach.
The above qualitative description of connection oriented vs
connectionless service serve only as examples to illustrate differing approaches. Work in the area of an integrated service model, QoS and resource reservation are related to but outside the scope of the IP
over ATM Work Group. This work falls under the Integrated Services
Work Group (int-serv) and Reservation Protocol Work Group (rsvp), and will ultimately determine when direct connections will be
established. The IP over ATM Work Group can make more rapid progress if concentrating solely on how direct connections are established. Cole, Shur & Villamizar Informational [Page 15]
6. Crossing IP Subnet Boundaries
A single IP subnet will not scale well to a large size. Techniques
which extend the size of an IP subnet in other media include MAC
layer bridging, and proxy ARP bridging.
MAC layer bridging alone does not scale well. Protocols such as ARP rely on the media broadcast to exchange address resolution
information. Most bridges improve scaling characteristics by
capturing ARP packets and retaining the content, and distributing the information among bridging peers. The ARP information gathered from ARP replies is broadcast only where explicit ARP requests are made.
This technique is known as proxy ARP.
Proxy ARP bridging improves scaling by reducing broadcast traffic,
but still suffers scaling problems. If the bridged IP subnet is part of a larger internetwork, a routing protocol is required to indicate what destinations are beyond the IP subnet unless a statically
configured default route is used. A default route is only applicable to a very simple topology with respect to the larger internet and
creates a single point of failure. Because internets of enormous
size create scaling problems for routing protocols, the component
networks of such large internets are often partitioned into areas,
autonomous systems or routing domains, and routing confederacies.
The scaling limits of the simple IP subnet require a large network to be partitioned into smaller IP subnets. For NBMA media like ATM,
there are advantages to creating direct connections across the entire underlying NBMA network. This leads to the need to create direct
connections across IP subnet boundaries.
Cole, Shur & Villamizar Informational [Page 16]
.----------.
---------< Non-ATM :
.-------. / /-< Subnet >-\
:Sub-ES >--/ : ---------- :
------- : :
: :
.--^---. .--^---.
:Router: :Router:
-v-v-- -v-v--
: : : :
.--------. : : .--------. : : .--------.
.-------. : >-/ \-< >-/ \-< : .-------.
:Sub-ES :---: Subnet :-----: Subnet :-----: Subnet :---:Sub-ES :
------- : : : : : : -------
-------- ---v---- --------
:
.--^----.
:Sub-ES :
-------
Figure 3: A configuration with both ATM-based and non-ATM based
subnets.
For example, figure 3 shows an end-to-end configuration consisting of four components, three of which are ATM technology based, while the
fourth is a standard IP subnet based on non-ATM technology. End-
systems (either hosts or routers) attached to the ATM-based networks may communicate either using the Classical IP model or directly via
ATM (subject to policy constraints). Such nodes may communicate
directly at the IP level without necessarily needing an intermediate router, even if end-systems do not share a common IP-level network
prefix. Communication with end-systems on the non-ATM-based
Classical IP subnet takes place via a router, following the Classical IP model (see Section 8.1 below).
Many of the problems and issues associated with creating such direct connections across subnet boundaries were originally being addressed in the IETF’s IPLPDN working group and the IP over ATM working group. This area is now being addressed in the Routing over Large Clouds
working group. Examples of work performed in the IPLPDN working
group include short-cut routing (proposed by P. Tsuchiya) and
directed ARP RFC-1433 [5] over SMDS networks. The ROLC working group has produced the distributed ARP server architectures and the NBMA
Address Resolution Protocol (NARP) [7]. The Next Hop Resolution
Protocol (NHRP) is still work in progress, though the ROLC WG is
considering advancing the current document. Questions/issues
specifically related to defining a capability to cross IP subnet
boundaries include:
Cole, Shur & Villamizar Informational [Page 17]
o How can routing be optimized across multiple logical IP subnets
over both a common ATM based and a non-ATM based infrastructure.
For example, in Figure 3, there are two gateways/routers between
the non-ATM subnet and the ATM subnets. The optimal path
from end-systems on any ATM-based subnet to the non ATM-based
subnet is a function of the routing state information of the two
routers.
o How to incorporate policy routing constraints.
o What is the proper coupling between routing and address
resolution particularly with respect to off-subnet communication.
o What are the local procedures to be followed by hosts and
routers.
o Routing between hosts not sharing a common IP-level (or L3)
network prefix, but able to be directly connected at the NBMA
media level.
o Defining the details for an efficient address resolution
architecture including defining the procedures to be followed by
clients and servers (see RFC-1433 [5], RFC-1735 [7] and NHRP).
o How to identify the need for and accommodate special purpose SVCs
for control or routing and high bandwidth data transfers.
For ATM (unlike other NBMA media), an additional complexity in
supporting IP routing over these ATM internets lies in the
multiplicity of address formats in UNI 3.0 [4]. NSAP modeled address formats only are supported on "private ATM" networks, while either 1) E.164 only, 2) NSAP modeled formats only, or 3) both are supported on "public ATM" networks. Further, while both the E.164 and NSAP
modeled address formats are to be considered as network points of
attachment, it seems that E.164 only networks are to be considered as subordinate to "private networks", in some sense. This leads to some confusion in defining an ARP mechanism in supporting all combinations of end-to-end scenarios (refer to the discussion in Appendix A on the possible scenarios to be supported by ARP).
7. Extensions to IP Routing
RFC-1620 [3] describes the problems and issues associated with direct connections across IP subnet boundaries in greater detail, as well as possible solution approaches. The ROLC WG has identified persistent routing loop problems that can occur if protocols which lose
information critical to path vector routing protocol loop suppression are used to accomplish direct connections across IP subnet
Cole, Shur & Villamizar Informational [Page 18]
boundaries.
The problems may arise when a destination network which is not on the NBMA network is reachable via different routers attached to the NBMA network. This problem occurs with proposals that attempt to carry
reachability information, but do not carry full path attributes (for path vector routing) needed for inter-AS path suppression, or full
metrics (for distance vector or link state routing even if path
vector routing is not used) for intra-AS routing.
For example, the NHRP protocol may be used to support the
establishment of direct connections across subnetwork boundaries.
NHRP assumes that routers do run routing protocols (intra and/or
inter domain) and/or static routing. NHRP further assumes that
forwarding tables constructed by these protocols result in a steady
state loop-free forwarding. Note that these two assumptions do not
impose any additional requirements on routers, beyond what is
required in the absence of NHRP.
NHRP runs in addition to routing protocols, and provides the
information that allows the elimination of multiple IP hops (the
multiple IP hops result from the forwarding tables constructed by the routing protocols) when traversing an NBMA network. The IPATM and
ROLC WGs have both expended considerable effort in discussing and
coming to understand these limitations.
It is well-known that truncating path information in Path Vector
protocols (e.g., BGP) or losing metric information in Distance Vector protocols (e.g., RIP) could result in persistent forwarding loops.
These loops could occur without ATM and without NHRP.
The combination of NHRP and static routing alone cannot be used in
some topologies where some of the destinations are served by multiple routers on the NBMA. The combination of NHRP and an intra-AS routing protocol that does not carry inter-AS routing path attributes alone
cannot be used in some topologies in which the NBMA will provide
inter-AS transit connectivity to destinations from other AS served by multiple routers on the NBMA.
Figure 4 provides an example of the routing loops that may be formed in these circumstances. The example illustrates how the use of NHRP in the environment where forwarding loops could exist even without
NHRP (due to either truncated path information or loss of metric
information) would still produce forwarding loops.
There are many potential scenarios for routing loops. An example is given in Figure 4. It is possible to produce a simpler example where a loop can form. The example in Figure 4 illustrates a loop which Cole, Shur & Villamizar Informational [Page 19]
will persist even if the protocol on the NBMA supports redirects or
can invalidate any route which changes in any way, but does not
support the communication of full metrics or path attributes.
.----. .----.
: H1 >----< S1 : Notes:
---- vvvv H#n == host #n
/ : \ R#n == router #n
/ : \ S#n == subnet #n
/------/ : \
: : \ S2 to R3 breaks
.--^---. .----. .-^--.
: : : R4 : : R6 :
: NBMA : --v- --v- See the text for
: : : : details of the
-v--v- = = looping conditions
: \ = SLOW = and mechanisms
: .-^--. = LINK =
: : R2 : = =
: --v- : :
: : .--^-. .--^-.
.-^--. : : R5 : : R7 :
: R8 : : --v- --v-
--v- \ : :
: \ / :
\ .-^^-. .--^-.
\ : S2 : : S4 :
\ --v- --v-
\ \ /
\ \ /
\ .^--^.
\ : R3 : path before the break is
\ -v-- H1->S1->R1->NBMA->R2->S2->R3->H2
\ /
.----. .-^^-. path after the break is
: H2 >---< S3 : H1->S1->R1->NBMA->R2->S2->R5->R4->S1
---- ---- \------<--the-loop--<-------/
Figure 4: A Routing Loop Due to Lost PV Routing Attributes.
In the example in Figure 4, Host 1 is sending traffic toward Host 2. In practice, host routes would not be used, so the destination for
the purpose of routing would be Subnet 3. The traffic travels by way of Router 1 which establishes a "cut-through" SVC to the NBMA next-
hop, shown here as Router 2. Router 2 forwards traffic destined for Subnet 3 through Subnet 2 to Router 3. Traffic from Host 1 would
then reach Host 2.
Cole, Shur & Villamizar Informational [Page 20]
新浪博客案例分析 董欢欢 目录 一、网络经纪概述 (2) （一）网络经纪的定义和特点 (2) （二）博客简介 (2) 二、新浪博客基本情况 (3) （一）简介 (3) （二）价值网络 (5) 三、新浪博客商业模式 (5) （一）战略目标 (5) （二）目标用户 (5) （三）产品和服务 (5) （四）盈利模式 (6) （五）核心能力 (10) 四、新浪博客经营模式 (10) 五、新浪博客技术模式 (11) 六、新浪博客管理模式 (12) （一）CEO的更替 (12) （二）企业文化 (12) 七、新浪博客资本模式 (13) 八、总结与建议 (14) 参考文献 (14)
一、网络经纪概述 （一）网络经纪的定义和特点 从大得范围上来说博客是SNS的一种表现形式。SNS有两种解释：一种是，Social Networking Services，即社会性网络服务，专指旨在帮助人们建立社会性网络的互联网应用服务。也应加上目前社会现有已成熟普及的信息载体，如短信SMS服务。另一种常用解释：全称Social Network Site，即“社交网站”或“社交网”。严格讲，新浪博客SNS并非Social Networking Services（社会性网络服务），而是Social NetworkSite（即社交网站）。 社会性网络(Social Networking)的早期理解是1967年，哈佛大学的心理学教授Stanley Milgram(1934～1984)创立的六度分割理论，简单地说：“你和任何一个陌生人之间所间隔的人不会超过六个，也就是说，最多通过六个人你就能够认识任何一个陌生人。”按照六度分隔理论，每个个体的社交圈都不断放大，最后成为一个大型网络。后来有人根据这种理论，创立了面向社会性网络的互联网服务，通过“熟人的熟人”来进行网络社交拓展，比如ArtComb,Friendster，W allop,adoreme 等。 （二）博客简介 关于博客(BLOGGER)的概念包括网络出版(Web Publishing),发表和张贴(Post--这个字当名词用时就是指张贴的文章)文章,是个急速成长的网络活动而且还出现了一个用来指称这种网络出版和发表文章的专有名词-----Weblog或Blog。一个Blog就是一个网页它通常是由简短且经常更新的Post所构成。这些张贴的文章都按照年份和日期排列。Blog的内容和目的有很大的不同从对其他网站的超级链接和评论有关公司、个人、构想的新闻到日记、照片、诗歌、散文,甚至科幻小说的发表或张贴都有。许多Blogs是个人心中所想之事情的发表其它Blogs则是一群人基于某个特定主题或共同利益领域的集体创作。Blog好象对网络传达的实时讯息。撰写这些Weblog或Blog的人就叫做Blogger或Blog writer。在网络上发表Blog的构想始于1998年但到了2000年才真正开始流行。起出Blogger将其每天浏览网站的心得和意见记录下来并予以公开来给其它人参考和
模板工程专项施工方案 一、工程概况： 项目总建筑面积110200.06m2，其中地上建筑面积89799.48㎡，地下建筑面积20400.58㎡，项目总投资约145414623.15元，17#-19#栋为剪力墙结构，地上34层，地下室为框剪结构，地下一层。 二、模板工程材料的选用 根据我单位常规的施工方法，结合市场材料供应情况，考虑施工质量的要求以及施工的易操作性，本工程模板工程采用的材料分别如下： 1、模板支撑体系：采用扣件式钢管满堂红脚手架作为模板水平和垂直支撑体系。具体构件的支撑方式详见后面的构件支模方法。 2、模板板村：为了保证工程质量及增加模板周转次数，决定采用18mm厚木胶合板。模板本身的质量直接牵涉到模板工程的质量和模板的周转次数，所以，木模板进货时必须严格把关。 3、木枋材料 本工程木枋采用60×80杉木枋材，直接购进成品，到现场再精加工，选购时必须注意木材的含水率必须低于25%，不得有翘曲变形现象。其它辅助材料的选择和要求在后面的方案中再说明。 三、具体的工艺要求和施工方法
(1)支模架的搭设 支模架采用扣件式钢管脚手架搭设方法。用来作梁和平板模板的竖向垂直支撑，同时也作柱和剪力墙的水平固定支撑。搭设的具体要求如下： 1、立管间距：对一般梁板，梁底两边的立管采用0.8×1.0米立柱网，平板下位柱可采用1.0×1.1平方米的立柱网，对深梁、厚板的特殊结构，通过计算采用更密的柱网或用其它方法加撑。 2、水平杆布设：离地150－25cm设一道扫地杆，纵横向布置，梁、板底部根据支模需要标高搭设一道水平杆，扫地杆和顶层水平杆之间应增加水平连结杆，纵横两向布置，水平杆的垂直距离不得超过1.6米。 3、剪刀撑布置：为加强整个支模架体系的整体稳定性，在满堂红架子中，纵横向均应设垂直方向剪刀撑，剪刀撑间距≤4.0米。 (2)柱模施工方法： 柱子模板采用单面腹膜板制成定型模板，柱箍采用6#槽钢和Φ14对拉螺栓。柱子的水平支撑利用满堂红支模架作为水平支撑，每柱水平支撑不得少于上、中、下三道，水平支撑的间距不得大于2米。 柱模的装配图详见下图：
2007 年电子科技大学校内数学建模竞赛题目 地铁杂散电流的分布 地铁以它的承载量大、快速、准时、占地少等特点被大家所青睐。但地铁也会带来安全、环境等问题。在环境方面的影响主要有共振和迷流等。 机车的驱动都是以电力为动力，电气机车接触网(第三轨)供电线路回路的结构如图1和图2所示。供电为1500V的直流电，通过地铁隧道顶的导电轨,机车顶上的电刷，给机车供电，通过隧道底部的钢轨实现回流。电流有可能泄漏到地下，形成地铁杂散电流（也称迷流）。 图 1 ：地铁地下结构示意图（纵截面） 图 2 ：地铁地下结构示意图（横截面） 某地的在建地铁工程设计希望解决以下两个问题： 1 ．如图1所示，假设只有一根钢轨做回流线，钢轨是直的，不考虑弯曲的情况。轨上有2000安培的稳恒电流流过。请你建立一个模型，来描述地下（请考虑地下物质的电导特性）迷流的分布情况。
2 ．地铁杂散电流一旦大量泄露出来，可能构成安全隐患。假设在距地铁的直线距离为150米的地方有一处摩天大楼，请你分析迷流对该建筑物的影响。 2006 年电子科技大学校内数学建模竞赛题目 想要有个家！！！ 假设你是今年毕业的大学生，已签了一家月收入 2500 元的成都公司，公司不能为你提供住房。父母为你提供了一笔资金，可以作为一个小户型的 5 万首付款。你面临一个抉择：是先租房住还是先按揭买房？ （ 1 ）请分析并预测不同地段的房屋租金、房价走势。 （ 2 ）结合当前银行贷款利率做出一个你认为比较好的决策。 （ 3 ）从长远的观点来看，为保证你的生活质量，应该怎样规划你的购房计划。 2005 年电子科技大学校内数学建模竞赛题目 圆明园：该怎样保护你 已经进行了两年的圆明园公园铺设防渗膜工程最近引起了社会各界的极大关注。一方认为，防渗处理隔断了水的自然循环，破坏圆明园的整体生态系统和园林风格；另一方认为这样做是为了更好地保护圆明园的生态环境。 请你在了解双方观点依据的基础上，提出你自己的见解，建立数学模型支持你的观点。 注意：所用资料一定写明出处。 背景资料（仅供参考）： 1. 圆明园历史从1709年开始营建，至1809年基本建成，历时一个世纪。此后的嘉庆、道光、咸丰三代屡有修缮扩建，历时150多年。圆明园总面积近352万平方米，水面面积约123万平方米。 2. 圆明园湖底防渗漏问题可以确定清河在圆明园的分布范围，在地下10.3米深度范围内，渗漏系数较大，渗水性较强。圆明园极为缺水，2000多亩的水面，每年枯水期约有七八个月，由于降水量少，很多植被旱死。经初步测算，如果圆明园要想保持水深是0.8米，总需水量合计为98.4万立方米；若常年保持1.5米深的水面，每年蓄水量为900万方。现在水务局能提供的水量是150万立方米。 3. 水费问题2004年8月1日前，北京市公园湖泊生态环境用水的收费标准是每立方米0.3元，现在环境用水涨到了每立方米1.3元。生态环境用水在城市用水
荷顿智能制造（太仓）有限公司年新增9500套智能化机器人焊接生产线、14200套精密型生产控制精度 设备扩建技改项目 高 支 模 专 项 施 工 方 案 编制人： 审核人： 批准人： 日期：
一、编制依据 (3) 二、工程概况 (3) 三、施工准备 (3) 四、主要部位支模方法 (3) 五、模板拆除 (8) 六、质量验收标准 (8) 七、模板安装技术措施 (10) 八、成品保护 (12) 九、安全文明施工 (13) 十、典型梁截面模板计算书 (14) 十一、典型板模板计算书 (27) 十二、典型梁侧模板计算书 (39) 十三、典型柱模板（设置对拉螺栓）计算书 (47) 十四、典型梁侧模板计算书 (56)
一、编制依据 （1）施工组织设计； （2）项目工程设计图纸； （3）《混凝土结构工程施工质量验收规范》GB50204-2015 （4）《扣件式钢管脚手架安全技术规范》JGJ130-2011. （5）《建筑施工手册》第五版 （6）《混凝土结构设计规范》GB50010-2012 （7）《建筑结构荷载规范》GB50009-2012 （8）《建筑施工安全检查规范》JGJ59-2011 （9）《建筑工程大模板技术规程》JGJ74-2008 （10）《建筑施工模板安全技术规范》JGJ162-2008 二、工程概况 本工程为荷顿智能制造（太仓）有限公司年新增9500套智能化机器人焊接生产线、14200套精密型生产控制精度设备扩建技改项目。 本工程包含1-3#车间及辅助用房及门卫。工程地址位于：太仓市浏河镇西部工业园区。建设规模19717.41平方米。地上四层，地下一层。建筑的火灾危险类别为丁类，耐火等级为二级。本次专项方案主要针对2#车间辅助用房高支模，此模板搭设高度达8米需进行专项方案编制并进行专家审查。 三、施工准备 3.1.技术准备 详细阅读图纸，了解工程特点，做好图纸会审和技术交底工作。参与并执行施工组织设计的工期要求，技术要求以及与其它专业工种相配合的重点注意事项。 3.2.现场准备 3.2.1 模板合模前，首先由水电等专业，对预埋管件验收检定无误后，再行合模。 3.2.2 支模前，必须弹线，包括轴线，300控制线，标高线。 3.2.3 检查钢筋绑扎质量，办好隐蔽工程记录，并要检查钢筋保护层厚度。 3.2.4安装模板前，应把模板面清理干净，刷好隔离剂。 3.3.机具准备 电钻3台，6KW，刨、车床２台12KW，电锯2台，６KW，其它相关机具现场确定。 3.4.材料准备 13mm木胶板； 40*90木方；Ф48*2.8钢管；扣件 四、主要部位支模方法 4.1.柱模板安装 本工程柱模板为13mm木胶板，40*90木方作竖向背楞，双钢管对拉螺栓固定。 4.1.1按照设计图纸，每个柱子预制好4片模板，木胶板宽度两边比柱截面小3mm，另外两边宽度为柱截面加两块木胶板的厚度。 4.1.2竖向背楞间距不大于250mm，对拉螺栓间距不大于600mm，下面一道螺栓距地200mm。 4.1.3支模前根据柱边线用钢筋在距地50m m左右，焊好柱断面撑，每边二根，并做 3
一、比赛时间：4月9-10日 二、比赛地点：学校乒乓球场地 三、比赛对象：四、五年级各班男女各2人（可各班先进行比赛再选出）。 四、比赛方法：男女单打比赛，采用淘汰赛的方式，三局两胜制，每局11分制。 五、比赛名次：取前八名 六、比赛分组：分四年级男、女组和五年级男、女组共4组（单打）。 七、组织形式：年段各班组织报名，报名时间3月31日之前，体育组负责组织比赛。 八、对阵表：采用抽签形式。 九、报名表 二、阳翟小学三人篮球赛方案 一、比赛时间：4月16-17日 二、比赛地点：学校篮球场地 三、比赛对象：五年级各班男女各1队（每队3-4人）。 四、比赛方法：进行两个阶段比赛，先进行小组循环赛再进行交叉淘汰赛 五、比赛名次：取前四名 六、比赛分组：五年级男、女组共2组。 七、组织形式：年段各班组织报名，报名时间3月31日之前，年段长组织年段观看比 赛。 八、对阵表：采用抽签形式 九、裁判员：体育组所用成员。 十、报名表
一、比赛时间：4月23-24日 二、比赛地点：学校田径场地 三、比赛对象：全校各班。 四、比赛方法：每生准备一条短绳，以年段为单位，一分钟跳绳，计算全班跳过绳子 的次数（班级和班级之间交换数跳过绳子的次数。） 五、比赛名次：取年段班级的前三名 六、比赛分组：按各年级分组。 七、组织形式：由年段各班组织，各年段长组织年段观看比赛。 八、出场比赛顺序：按班级号顺序进行，如一班比赛，二班帮忙计数。 九、裁判员：体育组协调组织，裁判另定。 四、阳翟小学排球自垫球比赛方案 一、比赛时间：拟定5月7-8日 二、比赛地点：学校田径场地 三、比赛对象：四、五年级各班男女各4人。 四、比赛方法：分男女组，自垫一次机会，时间不限，以自垫球多的为胜。 五、比赛名次：取各人前八名 六、比赛分组：分男女两大组别。 七、组织形式：由年段各班组织，报名时间截止4月30日。各年段长组织年段观看比 赛。 八、出场比赛顺序：按抽签顺序出场比赛。 裁判员：体育组协调组织，裁判另定。 九、报名表
R-10.2(2)-07 城际新苑（万科环球 村）二期工程 铝合金模板 专项施工方案 编制人员: 上海建工五建集团有限公司 2014年07月
目录 一、工程概况 (2) 1.1 工程名称 (2) 1.2 工程地址 (2) 1.3 建设单位 (2) 1.4 设计单位 (2) 1.5 监理单位 (2) 1.6 施工单位 (2) 1.7 工程概况 (2) 二、编制依据 (2) 三、编制说明 (3) 四、前期准备 (3) 五、铝合金模板技术特点 (4) 六、具体的工艺要求和施工方法 (4) 七、铝合金模板的拆除 (7) 八、质量保证措施 (8) 九、安全及环保措施 (9) 十、注意事项 (10) 十一、铝模节点图片 (11) 铝合金模板施工方案
工程概况 1.1 工程名称城际新苑（万科环球村）二期工程 1.2 工程地址 本工程位于长沙市雨花区劳动东路北侧，万科环球村一期以东 1.3 建设单位 湖南湘诚壹佰置地有限公司 1.4 设计单位 广东华玺建筑设计有限公司 1.5 监理单位 深圳市邦迪工程顾问有限公司 1.6 施工单位 上海建工五建集团有限公司 1.7 工程概况 本工程4栋34层高层住宅楼，总建筑面积102945.49m2,其中地上部分面积86307.72 m2,地下室面积16637.77m2。本工程建筑土0.000相当于绝对标高为+38.300叶9-12#楼2层--34层为铝模施工。 （6）基坑等级：本工程基坑安全等级三级，环境保护等级三级. 二、编制依据 业主提供的城际新苑（万科环球村）二期9-12#栋及地下室工程施工图纸 城际新苑（万科环球村）二期9-12#栋及地下室工程《施工组织设计》建筑结构荷载规范》GB 50009-2012 混凝土结构设计规范》GB 50010-2011 混凝土结构工程施工质量验收规范》GB 50204-2011 建筑工程施工质量验收统一标准》GB 50300-2011 建筑施工高处作业安全技术规范》JGJ 80-91 建筑施工安全检查标准》（JGJ59-2011）模板早拆体系施工技术规程》（DB11/694-2009） 万科集团《质量标准及实测实量方法》 三、编制说明 全铝合金模板有利于环保，节约木材，保护树林，可多次再利用，符合国家节能减排政策，且铝模具有自重轻，承载力高，施工容易，维护费用低，施工效率高，混凝土表面质量好，
x x x x x x x x项目 模板支撑专项施工方案 编制：＿＿＿＿＿＿＿＿ 审核：＿＿＿＿＿＿＿＿ 审批：＿＿＿＿＿＿＿＿ xxxxxxxx项目部 2013年12月16日 目录 一、编制依据 (4) 二、工程概况 (4) 三、施工准备 (4) 3.１.技术准备 (4) 3.2.现场准备 (4) 3.3.机具准备 (4) 3.4.材料准备 (4) 四、主要部位支模方法 (5) 4.1 柱模板安装 (5) 4.2梁板模板安装 (5) 4.3剪力墙模板安装 (8) 4.4楼梯模板安装 (9) 4.5门窗洞口及预留洞模板 (10)
五、模板拆除 (13) 六. 质量验收标准 (14) 6.1模板加工质量要求 (14) 6.2现浇结构模板安装质量 (15) 6.3预埋件与预留洞口模板质量 (15) 6.4模板安装观感质量 (15) 七、模板技术措施 (16) 7.1 进场模板质量标准 (16) 7.2 模板安装质量要求 (16) 7.3、其它注意事项 (19) 7.4、脱模剂及模板堆放、维修 (20) 八. 成品保护 (20) 九. 安全文明施工 (21) 十．模板计算书 (22) 一、编制依据 （1）施工组织设计； （2）项目工程设计图纸； （3）《混凝土结构工程施工质量验收规范》 GB50204-2002（2011版） （4）《扣件式钢管脚手架安全技术规范》 JGJ130-2011. （5）《建筑施工手册》第四版 （6）《混凝土结构设计规范》 GB50010-2002 （7）《建筑结构荷载规范》 GB50009-2001 （8）《建筑施工安全检查规范》 JGJ59-2011 （9）《建筑工程大模板技术规程》 JGJ74-2003 （10）《建筑施工模板安全技术规范》 JGJ162-2008 二、工程概况 本工程为xxxxxxxx。本工程总建筑面积：17120㎡，地下一层，地上九层，总建筑 高度 38.1m。本工程结构形式：框架--剪力墙结构。
机械与电子工程学院技能竞赛总结 为了充分展示学生的才华与技能，引领学生热爱学习、立志成才，掀起勤学技术、苦练技能的学习热潮；同时增强教师团队的凝聚力，提高教师专业技能水平，机械与电子工程学院积极响应学校号召，于2015年12月7日至12月27日，举办了机电学院首届学生技能竞赛节活动。由于我院专业较多，共分为 3 个专业承办小组 4 个比赛项目：电子组的电子设计制作大赛、数控组的机械制图大赛、计算机组的打字比赛和网页设计大赛。在学院领导的关心与支持下，在全院各位同仁的共同努力，此次活动取得了极大的成功。现总结如下： 一、技能竞赛的组织，策划，宣传 1、组织策划细致，方案合理可操作在接到学校下达举办首次技能竞赛通知伊始，12 月11 日学院肖书记就专门召开了技能竞赛动员大会，要求各专业按照学校要求，积极筹备技能大赛。为此各专业教研室根据本专业的情况，组织了2-3 次专题会议，研究制定比赛任务，从宣传、报名、组织、评审、预算等方面做了详细的计划，并及时上交了合理又可操作的竞赛方案。 2、加大宣传力度，学生踊跃参赛 为切实营造技能竞赛氛围，突出职业教育和专业特色，使宣传工作达到预期的效果，各专业教研室对所有在校园内的宣传点做到了精心设计，严格把关，准确把握宣传内容与职业教育的意义和作
用，将本次大赛的目的和要求以及我院专业特点紧密结合起来。同时合理安排横幅、海报等作了仔细、合理的布置，突出体现了既美观大方，又符合视觉特点。计算机协会的同学手绘了 3 张海报张贴在校园食堂、实训室门口等重要位置，同时积极与学院及四校学工联系，通过班级将竞赛精神宣传到每一位同学，达到了很好的宣传效果。电子专业教研室还邀请了我院校企合作单位——合力泰有限公司指导此次大赛，为此合力泰还特意为此次比赛制作了祝贺横幅。 由于宣传到位，本次竞赛 4 个比赛项目共吸引了一院四校约二百多名同学踊跃报名参赛。 3、积极部署训练，提高比赛质量 大赛的目的是以赛促学，以赛促教。而各专业教师也利用这个契机，根据比赛方案，制订训练计划，充分利用课余时间开展训练。电子专业社团的同学早在国庆休假刚结束，就利用每周的周三和周五下午定点在 3 号实训楼402进行专业培训。计算机组的竞赛由于比赛面向全校，参赛人数众多，老师就动员计算机协会同学在赛前对参赛选手进行了 2 批次的培训。 二、技能竞赛的过程及结果 1、电子组——电子设计制作大赛电子设计制作大赛大胆尝试引入企业的产品标准作为衡量学生竞赛水平的优差。职业教育的输出直接对准的是市场，是企业，不能单纯的以课本标准作为竞赛的评选参照，市场的需求才是评价优差的唯一标准。因此我们电子组的比赛特意邀请了校企合作单位的合力泰有限公司的曾总工程师作为评审组
**万科*****项目 后期第*****组团 干法砌筑工程施工方案 编制单位：*******建筑工程总公司 编制：审核：审批： 日期：2012年04月10日
目录 一、工程概况 (1) 二、加气混凝土砌块使用部位 (1) 三、施工总体计划 (1) 四、作业条件 (3) 五、砌体质量要求 (3) 六、材料现场堆放及加气混凝土砌块龄期要求 (4) 七、加气混凝土砌块操作工艺 (4) （一）工艺流程 (4) （二）、CL干法施工技术要点 (5) （三）、细部做法 (8) 八、砖砌体质量保证措施 (14) 九、墙体裂缝防渗措施 (15) 十、成品保护 (15) 十一、安全规定 (16)
一、工程概况 万科*************组团工程位于******************小区，建设单位为*****万科房地产开发有限公司，监理单位为********监理有限公司，设计单位为*******建筑设计院，承建单位为********建筑工程总公司 本项目建筑面积为43390m2，为4栋 9层砼框剪结构住宅楼，包括第**组团1#楼、2#楼，第**组团1#楼、2#楼，没有地下室，建筑物层高2.9米，建筑高度26.4米。 本项目计划施工工期： 2012年5月4日开工，2013年9月30日竣工。 二、加气混凝土砌块使用部位 加气混凝土砌块适用于各类建筑地面（±0.00）以上的内外墙和地面以下的内隔墙（有特殊要求的墙体除外），但如不采取有效的防护措施，不得在以下部位使用： 1、建筑物±0.00以下（地下室的非承重内隔墙除外）部位。 2、长期浸水或经常干湿交替的部位。 3、受化学侵蚀的环境，如强酸、强碱或高浓度二氧化碳等的环境。 4、砌块表面经常处于80℃以上的高温环境。 5、屋面女儿墙。 本工程内外墙体均采用加气混凝土砌块砌筑，其强度等级MU≥5.0；根据**万科项目部要求，****项目所有加气混凝土砌块砌体工程采用CL干法施工。砌筑砂浆强度等级为M5。 三、施工总体计划 按照工期节点，第*组团于*******开始砌筑墙体，*******完成，其中1#楼的C段的样板间*********开工，********完工；第*组团砌筑墙于****开工，***完工。 本工程砌体施工拟采取流水作业的施工方法。主楼部分砌体可在主体施工至第四层时，即穿插墙体施工。墙体采用逐层施工，每层砌体完成后，除留部分人员进行下一工
外商独资XXXXXX有限公司 章程 第一章总则 第一条根据《中华人民共和国公司法》、《中华人民共和国外资企业法》及中国其他有关法律、法规，制定本章程。 第二条股东名称：XXXXX 英文名称：XXXX 公司编号：XXXX 在香港登记注册，法定地址：XXXXX 电话：XXXXX 传真：XXXX 现任董事：XXXX 职务：董事国籍：XXXX 第三条外商独资企业名称：XXXX（以下简称公司）。 公司法定地址：深圳市前海深港合作区前湾一路1号A栋201室（入驻深圳市前海商务秘书有限公司）。 第四条公司为有限责任公司，是XXXX投资经营的企业，并以其认缴的出资额承担企业责任。 第五条公司经审批机构批准成立，并在深圳市登记注册，为企业法人，应遵守中华人民共和国的法律、法规，并受中国法律的管辖和保护。 第二章宗旨和经营范围 第六条公司宗旨：本着加强经济合作和技术交流的愿望，促进中国国民经济的发展，并获取满意的回报。 第七条公司经营范围：XXXX。 第三章投资总额和注册资本 第八条公司的投资总额为：XXXX 公司注册资本（出资额）为：XXXX 公司注册资本的出资方式及期限，按《中华人民共和国公司法》及中国其他有关法律、法规的规定执行。其中： 现金：XXXX（以等值外币出资，按缴款当日中国人民银行公布的基准汇率折算）； 股东出资的XXXX应于XXXX年XX月XX日之前实际缴付到位，现本股东承诺在约定的时间内按期缴付全部出资，逾期不到位的，自愿按法律承担相应责任。 第九条股东缴付出资后三十天内，应当委托中国注册会计师事务所验证，并出具验资报告，报审批机关和工商行政管理机关备案。
第十条公司在经营期内，不得减少注册资本。但是，因投资总额和经营规模等发生变化，确需减少的，须经审批机构批准。 第十一条公司变更经营范围、分立、合并、注册资本增加、转让或者其他重要事项的变更，须经公司股东决议通过后，报原审批机构批准，并在规定期限内向工商行政管理、税务、外汇、海关等有关部门办理相应的变更登记手续。 第四章股东职权 第十二条公司股东决定公司的重大事项，依照公司法和本章程规定，通过股东决定行使下列职权： （一）决定公司的经营方针和投资计划； （二）委派和更换非由职工代表担任的董事、监事，决定有关董事、监事的报酬事项； （三）审议批准董事会的报告； （四）审议批准监事的报告； （五）审议批准公司的年度财务预算方案、决算方案； （六）审议批准公司的利润分配方案和弥补亏损方案； （七）对公司增加、减少或者转让注册资本作出决议； （八）对发行公司债券作出决议； （九）对公司合并、分立、延期、解散、清算或者变更公司形式作出决议；（十）修改公司章程； （十一）其他应由股东决定的重大事宜。 第五章董事会 第十三条公司设立董事会。董事会负责执行公司的一切重大事项，并向股东负责。 第十四条董事会由3名成员组成，其中董事长１人。董事长及董事由股东委派及撤换。董事长和董事每届任期3年。经继续委派可以连任。董事人选的更换，应书面通知董事会，并向公司登记机关备案。 第十五条董事长是公司的法定代表人，是代表公司行使职权的签字人。董事长在董事会闭会期间，依照企业章程和董事会决议，处理公司的重大问题，负责检查、监督董事会决议的执行情况。董事长临时不能履行职责的，委托其他董事代为履行，但应有书面委托。法律、法规规定必须由董事长行使的职责，不得委托他人代行。 第十六条董事会对公司股东负责，行使下列职权： (一)执行股东决定； (二)决定公司的经营方针、发展规划和投资方案，审批经理或管理部门提出
模板工程专项施工组织设计（范本） 注：本专项施工组织设计所包含的内容（含公式、数据等）仅供参考，项目部在编写同类型专项施工组织设计时可参照本专项施工组织设计的编排格式，同时应根据工程项目的实际情况酌情增减有关内容。 1、编制依据 （1）《木结构工程质量验收规范》（GB50206－2002） （2）《混疑土结构工程施工质量检验规范》《GB50204—2002) （3）《建筑结构荷载规范》(GB50009－2001) （4）《混凝土模板胶合板》（GB/T17656-1999） （5）《建筑施工安全检查标准》（JGJ59-99) （6）《建筑施工扣件式钢管脚手架安全技术规范》（JGJ130-2001） （7）《钢管脚手架扣件》(GB/T15831-1995) （8）《高处作业安全技术规范》（JGJ80-91） 2、工程概况 工程名称：XX公园管理配套用房工程 工程地点：XX区XX路XX号 建设单位：上海市XX区园林管理处 设计单位：XX设计咨询有限公司 监理单位：上海XX建设监理有限公司 施工单位：上海金鹿建筑实业有限公司 本工程主楼地下一层，箱形框架结构，地上二层，副楼地上二层，均为框架结构。层高：头层4.4米，二层4米，建筑总高度：主楼10.4米，副楼9.4米，室内外高差：主楼1米，附楼0.30米，建
筑总面积：2236米2。基础埋置深度：主楼-2.75米，附楼-1.70米，基础结构：主楼为箱形片筏基础，副楼为条形基础。模板支撑采用钢管（Φ48×3.5mm）扣件连接，排架支撑组合。模板采用胶合板，横楞采用（50×100mm）方木，搁栅采用钢管（Φ48×3.5mm）扣件连接，采用Φ14对铰螺栓加固。 3、模板施工 用胶合板拼成较大模板，加工前，绘制模板制作图和组装图。首先，根据墙、柱及板宽，确定小木楞长度(方木尺寸50×100mm)，间距200~300mm，用园钉将九夹板固定在小木楞上，拼装好的模板编号并注明使用部位，然后用塔吊运至相应位置拼装。 （1）垫层模板由于基础垫层面积较大，混凝土浇筑后垫层面不可能在同一水平上，因此在模板的下端统长铺设一根（50×100mm）方木。采用水平仪进行找平，木条下部每2米留一个排水孔（30×50mm）以便于将混凝土浇灌时产生的余水和浮浆排出坑外。 （2）基础模板 1）模板边线放线后，必须由技术质量人员进行技术复核，无误后才能支模。模板采用胶合板拼组，内木楞采用竖向（50×100mm）方木，间距：300mm；外木楞采用双钢管（Φ48×3.5mm）上下二道加Φ14螺栓，月牙扣件固定，水平间距500mm。竖杆、水平支撑，斜杆支撑固定。 2）地下室墙模板，外墙施工缝留在底板面上250mm处，地下室模板，采用胶合板，根据墙板相应尺寸组合拼装成整体，模板内木楞采用50×100mm方木作竖向木楞，间距300mm，横向外木楞采用双钢管（Φ48×3.5mm）间距600mm加Φ14螺栓，水平间距500mm，月牙扣件进行固定，模板排架纵横向水平杆支撑，纵横向剪力撑加固连接。
用最简单的方法找到优质股 【编者按】最近股市跌多涨少，面对这样的行情又该如何把握手中的股票呢？香港投资评论家曹仁超提出牛市开始进入牛市第二期，在这样的市场行情下，老曹提出优质股千万别减仓，你的股票中有没有他提到的优质股呢？在跌市中如何才能赚到钱这里一一为你解读。 曹仁超：牛市二期炒股不炒市优质股千万别减仓 香港投资评论家曹仁超日前接受中国证券报记者采访时表示，2008年11月到2009年8月是牛市第一期，表现特征是“快上快落”。如果说从2010年7月2日开始牛市二期的话，那么其特征将是“慢上而不落”。他认为，未来全球资金将流向新兴市场股市，而非金市等低风险领域。 “持有的是优质股千万不可逢高减仓，小心卖掉后买不回来。” 牛市二期炒股不炒市 曹仁超指出，根据波浪理论，牛市一期调整阶段最大下调幅度应是前期升幅的61.8%。依此推算，上证指数应在2300点左右获得支持，此乃今年7月初他本人力排众议认为“短期见底信号已出现”的理由。今天看来，越来越多的人认为牛市一期的调整阶段已经结束，这也是近日A股市场持续上升的理由。 牛市一期的时候，A股指数在投资者的恐慌中上升，因为当时经济情况仍在转坏中，只是股市抛售力量在减弱。例如2008年11月至2009年8月间，只有资深投资者在吸纳。到一般人因经济情况日渐好转而改为看好股市，并入市吸纳股票时，资深投资者便开始获利回吐，令股市出现下调，幅度达到前期升幅的三分之一、二分之一甚至61.8%。具体下调幅度大小要视客观形势而定，事前并不能知道。股市出现下调，小投资者再次出现恐慌并加入抛售行列，例如2009年8月到2010年6月。但是到今年7月，资深投资者发现抛售力量再次减弱，便入市吸纳。牛市一期快上快落，假设从7月2日开始牛市二期，其特征则是慢上而不落，或下调幅度很少。 牛市二期的投资策略是选择性投资，即个别股份上涨或下跌，但整个大市是反复上升的。如吸纳的是优质股，应该持货不卖；如吸纳的是跑输大市的股票，便应该及时出售。牛市二期是炒股不炒市，如持有的是优质股千万不可逢高减仓，小心卖掉后买不回来。 资金将流入新兴市场股市 对于中国上调工人工资会否影响中国的竞争力的问题，曹仁超表示，中国劳动市场相信已进入刘易斯拐点(即来自农村的廉价劳动力供应在减少中，30年改革开放政策令教育晋
2007年中南大学数学建模竞赛题 A题西部地区农村建设规划问题 在我国西北部某些干旱地区，水资源量不足是发展农牧业生产的主要限制因素之一。紧密配合国家西部大开发和新农村建设的方针政策，合理利用水资源，加强农田水利工程建设，加速西部农牧业发展，这是当地政府的一个重要任务。在水利工程建设中，如何合理规划，发挥最大的水利经济效益，是值得研究的一个问题。现有问题如下： 问题1：某地区现有耕地可分为两种类型，第Ⅰ类耕地各种水利设施配套，土地平整，排灌便利；第Ⅱ类耕地则未具备以上条件。其中第Ⅰ类耕地有2.5万亩，第Ⅱ类耕地有8.2万亩，此外尚有宜垦荒地3.5万亩。该地区主要作物是小麦，完全靠地表水进行灌溉。由于地表水的供应量随季节波动，在小麦扬花需水时恰逢枯水季节，往往由于缺水使一部分麦田无法灌溉，影响产量。而且由于第Ⅱ类耕地条件差，土地不平整，所以灌溉定额高，浪费水量比较大，并且产量还不及第Ⅰ类耕地高。进一步合理利用水资源的措施有二：其一是进行农田建设，把一部分第Ⅱ类耕地改造成为第Ⅰ类耕地，以节约用水，提高单产；其二是修建一座水库，闲水期蓄水，到小麦扬花需水的枯水期放水，从而调节全年不用季节的水量。目前该地区在整个小麦生长期的地表水资源可利用量为96.5百万方，其中小麦扬花需水季节可供水量为7.5百万方。水库建成后在小麦扬花需水季节可多供水量为6.5百万方。修建水库需要投资5.5百万元，将第Ⅱ类耕地改造为第Ⅰ类耕地每亩需要投资20元，将荒地开垦为第Ⅱ类耕地每亩需要投资85元，将荒地直接开垦为第Ⅰ类耕地每亩需要投资100元。规划期内，计划总投资额为9百万元。该地区对小麦的需求量及国家征购指标共计2万吨，超额向国家交售商品粮每吨可加价100元。各种条件下水的灌溉额及净收益情况如下表1： 表1：规划年各种条件下的灌溉定额及净收益
模板工程 施 工 方
一、编制依据： 1、青海省土木建筑设计院有限公司提供的河南县蒙藏医院制剂中心及附属设施建设工程设计图纸 2、河南县蒙藏医院制剂中心及附属设施建设工程施工组织设计 3、建筑地基基础工程施工质量验收规范（GB50202-2002） 4、人防工程施工及验收规范（GBJ134-90） 5、建筑施工手册(缩微版第二版) 6、混凝土结构工程施工质量验收规范（GB50204-2002） 7、建筑施工高处作业安全技术规程（ 8、建筑混凝土结构技术规程（ 9、建筑安装工程资料管理规程（ 3层局部4层。制剂车间2385.37 ㎡，建筑高度6.65M；建筑层数为 传统工艺车间749.4 ㎡，建筑高度3.0M，建筑层数 1、 梁板采用木胶合板； 2、流水段划分： 12、地上地下划分详见《河南县蒙藏医院制剂中心及附属设施建设工程 施工组织设计》。 五、施工准备工作： 1、技术准备：
（1）、根据施工组织设计、施工图纸要求计算模板配置数量，确定各部位模板施工方法，编制模板 设计施工方案。 （2）、技术负责人及主管工长对操作班组做好方案、技术交底岗前培训，明确模板加工、安装标准 及要求。 （3）、根据施工进度，技术员提前制定模板所需材料进场计划。 2、生产准备： （1）、人员准备： 2、墙柱木模板应放置在模板插口架内，插口架做法见【模板插架搭设图】附图。（4）、运输准备：多层板在加工区组装成模板，包括柱模、梁帮板，然后用自制手推车推至现场， 现场安装用塔吊吊运。 (５)、预埋准备： a.框架柱、墙体木模板支模时，地锚用25的钢筋头长度为400mm（漏出混凝土面200mm），离框架柱、墙体根部200mm，1500mm，2500mm，3500mm埋第一、第二、第三、第四排，纵向间距1000mm。 b.严禁在抗渗混凝土内预埋钢筋地锚。
原来最好的指标就是免费的指标--------zhuan 2011-01-07 08:33:36| 分类：股票类 | 标签： |字号大中小订阅 我想告诉大家的是：最好的指标已经在各位的系统里了！ 我用的是通达信，我经过13年时间同大家一样到处找指标，研究指标，到组合指标，最后才知道什么叫经典指标，就是系统里预装的这些，我们“看不懂又不准”的指标。 这里我想推荐大家仔细体会的指标有4个，如果这四个指标都体会透了，那赚钱就已经不是问题了，只是赚多和赚少的事,更有可能让你吃完一只股80％-90％的波段。 这 4 个指标是： 最灵敏的短线指标：【CCI】 中长线顶底判断指标：【DMI】庄家如果想用这个指标骗线的话，估计成本很高短中长线趋势判断指标：【薛斯通道】，【薛斯通道II】 这里大家可以把【薛斯通道II】作为主图，【CCI】,【DMI】,【薛斯通道】作为附图，研究【薛斯通道II】的短期轨道和长期轨道的关系，再加上【CCI】指标就可以进行短线买卖，通过【DMI】,【薛斯通道】【薛斯通道II】可以找到中长线的买卖点。更多的东西，只有大家自己将系统调整好，调出要跟踪的股票慢慢研究，相信你会有很大收
获， ======================================== 大家都希望指标不仅在牛市中使用，更希望在熊市中也可以有好的收益，下面我举一个在熊市中使用的例子
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝ 请将以下源码通过指标管理器设置成附图指标 【薛斯通道】 {参数n 2 120 13} VAR2:=CLOSE*VOL; VAR3:=EMA((EXPMA(VAR2,3)/EXPMA(VOL,3)+EXPMA(VAR2,6)/EXPMA(VOL,6)+EXPMA(VAR2,12 )/EXPMA(VOL,12)+EXPMA(VAR2,24)/EXPMA(VOL,24))/4,N); SUP:1.06*VAR3; SDN:VAR3*0.94;
山西建筑职业技术学院 物业管理专业技能大赛校内选拔竞赛方案 为参加全国房地产类专业指导委员会即将在上海举办的首届全国高职和中职物业管理专业技能竞赛，我校工管系在物业管理专业中积极选拔参赛选手，拟举行校内参赛选手选拔竞赛。 一、竞赛名称 山西建筑职业技术学院物业专业技能大赛参赛选手选拔竞赛 二、竞赛目的和原则 依据高职高专和中等职业教育物业管理专业培养目标与教学内容，构建职业技能的评价指标体系，展示职业教育教学成果，促进我院物业管理专业职业教育水平的整体提升。 技术技能竞赛设置的基本原则： 1.竞技性原则：比赛的赛项和内容安排能够体现出技术水平的高低和优劣。 2.引导性原则：竞赛能够展现物业管理专业的核心知识、基本技能及综合素质，能够对专业的人才培养目标和核心能力有一个明确定位，围绕知识、技能、素质展开。 3.交流性原则：竞赛不仅是一个竞技的平台，更是一个学生之间、教师之间学习和交流的平台。 4.职业性原则：以职业岗位能力要求为落脚点，紧密结合岗位实际。竞赛的赛项内容取自岗位上的工作任务。 三、竞赛方式与内容 （一）参赛学生范围 工程管理系物业管理专业全体学生 （二）竞赛内容 本次竞赛依据教育部高职和中职物业管理教学基本要求，以及全国房地产类专业教育教学指导委员会关于举办物业专业技能竞赛的要求，制定本次技能大赛选拔赛实施规程。
1.总则 此次竞赛分知识竞赛、技能竞赛和综合能力竞赛3个部分，其中知识竞赛分值占总分的30%，技能竞赛分值占总分40%（包括照明系统故障排除和消防设备操作2大模块）综合能力分值占总分的30%。 2.竞赛项目 2.1知识竞赛 以全国物业管理师考试应具备的知识和技能要求为基础，结合高职和中职院校物业管理专业的教学和学生未来就业所需进行考核。知识竞赛采用闭卷方式进行，时间为60分钟。 2.2技能竞赛 技能竞赛采取现场实操的方式进行，竞赛内容围绕设施设备安装、故障排除等内容为主，具体包含2大模块，即：照明系统故障排除（2人）和消防设备操作（2女2男）。参赛选手必须在规定的时间内完成规定的任务。并按照成果质量和比赛用时作为竞赛的计分内容。 2.3综合能力竞赛 综合能力竞赛表现形式为情景表演，参赛学生根据所提供的案例，现场即时表演，根据参赛学生处理案例所运用的知识技能的恰当与否，以及表演过程中的表现能力，对参赛者进行评价。 四、竞赛规则 1、参赛人员凭身份证、学生证参加比赛，比赛过程中不得更换参赛人员。 2、参赛团队必须提前20分钟进入赛场，到检录处检录，抽签决定比赛号位。开赛前10分钟停止检录，未能检录者取消比赛资格。 3、竞赛使用语言为普通话，选拔赛自备服装。 4、参赛者必须独立完成所有比赛内容，比赛过程中不得使用任何通讯工具与外界交换信息。 5、参赛队必须服从裁判，若有争议可以在赛后向仲裁员申诉。
一、工程概况 工程名称：万科云鹭湾II-8地块 工程建设地点：宁波云鹭湾II-8地块位于慈城新城环湖以南，被人工河渠分为两块。 工程概况：宁波云鹭湾II-8地块位分别有商业、别墅、多层组成。总建筑面积为69892.19平方，其中地上为58630.98平方,地下为11261.21平方，其中别墅和商业为毛坯交付，6幢多层为装修交付。 工程建设主要参与方： 建设单位：宁波江北万科置业有限公司 设计单位：宁波市东方建筑设计院有限公司 监理单位：上海天佑工程咨询有限公司 施工单位：杭州市工程建设集团有限公司 勘察单位：核工业金华工程勘察院 二、编制依据 依据<<万科门窗塞缝的技术要求及标准做法>>《建筑工程施工质量验收统一标准》（GB50300-2001）和《建筑装饰装修工程质量验收规范》（GB50210-2001） 三、施工流程 1、门窗塞缝施工前，应做好门窗塞缝的工序样板，对工序样板组织淋水检验，按施工图纸做法，调整洞口尺寸，根据保温层的厚度，计算增加门、窗侧面的洞口放大尺寸，按调整后的洞口尺寸、洞口位置、标高对施工人员进行技术交底。 2、门窗框固定件形状标准，保证立框前固定件为规范的“U”字形，及时纠正每一个变形的固定件，使之成为“U”字形，固定件应内高外低。门窗框固定件安装完毕后应进行工序验收，并做好验收记录。 3、塞缝前保证缝隙垃圾清理彻底，剔除浮浆及表面的碎渣，用毛刷扫除阴角容易残留的垃圾，塞缝前清除缝隙杂物并浇水润湿，并在界面处用水泥浆扫浆。清理并扫浆后应做工序验收，做好验收记录。 4、门窗采用1:2干硬性水泥砂浆塞缝，掺防水剂，加10%的微膨胀剂，塞缝分两次进行。第一次塞缝至门窗框表面凹进3mm；第二次塞缝至与门窗框平，用直径15mm的PVC 管勾槽。门窗框与墙体间的缝隙填嵌饱满密实，表面平整。
承诺书 我们仔细阅读了中国大学生数学建模竞赛的竞赛规则. 我们完全明白，在竞赛开始后参赛队员不能以任何方式（包括电话、电子邮件、网上咨询等）与队外的任何人（包括指导教师）研究、讨论与赛题有关的问题。 我们知道，抄袭别人的成果是违反竞赛规则的, 如果引用别人的成果或其他公开的资料（包括网上查到的资料），必须按照规定的参考文献的表述方式在正文引用处和参考文献中明确列出。 我们郑重承诺，严格遵守竞赛规则，以保证竞赛的公正、公平性。如有违反竞赛规则的行为，我们将受到严肃处理。 我们参赛选择的题号是（从A/B/C中选择一项填写）： C 我们的参赛报名号为（如果赛区设置报名号的话）： 所属学校（请填写完整的全名）： 参赛队员(打印并签名) ：1. 2. 3. 指导教师或指导教师组负责人(打印并签名)：数模组 日期： 2012 年 8 月 20 日赛区评阅编号（由赛区组委会评阅前进行编号）：
编号专用页 赛区评阅编号（由赛区组委会评阅前进行编号）： 全国统一编号（由赛区组委会送交全国前编号）：全国评阅编号（由全国组委会评阅前进行编号
游船业务优化设计模型 摘要 旅游业是一种集多种产业和功能于一体的综合产业，乘游船旅游作为旅游业务中的朝阳产业，它与经济的发展有着密切的联系。合理地选择游船规模与制定订票策略成为提高游船效益的关键，本文根据收益最大化原则，利用数值积分模型，用matlab 软件编程对游船最大规模问题进行了求解。 在求解问题一中三种游船业务的最佳规模时，本文首先采用MATLAB软件编程画出三种游船乘坐人数的正态分布图，观察其分布特点，从而确定出有效的求解方法；其次设出游船最佳业务规模M，建立数值积分模型表示出了每个区段游船的购票人数，根据题意确定成本,利用最大收益原则，进而确定收益的数值积分模型，利用matlab软件编程分别求出了三种游船的最佳业务规模，用matlab工具箱绘制出游船收益图。 在求解问题二中A→C游船业务的最佳规模时，根据问题一中的方法分别建立出短途旅程A→B、B→C的收益的数值积分模型，对两者进行求和，利用matlab软件编程求出A→B、B→C段相等的游船最大业务规模，再与问题一中求出的A→C的最大规模求和，从而求解出 A→C游船业务的最佳规模为826。 在制定问题三中的订票策略时，为减小空座率，我们首先设定A→B、B→C的限售票额为都为m,则A→C 的限售票额为826-m,进而根据问题一中的求解方法确定游船A→C的总体最大收益的数值积分模型，利用matlab软件编程解出A→B、B→C的限售票额m均为267，A→C的限售票额为559，即为游船制定的订票策略。 关键词：收益最大化数值积分 MATLAB软件正态分布概率密度函数