Lec1

LEC（一）风险评估法LEC法是一种常用的风险评估方法，可采取计算每一项已辨识出的危险源所带来的风险。

其风险值D由三个主要因素L、E、C的指标值的乘积表示，即D=LEC。

L——发生事故的可能性大小。

事故发生的可能性大小用概率来表示时，绝对不可能发生的事故概率为0，必然发生的事故概率为1，因此人为的将发生事故可能极小的分数定为0.1，必然要发生事故的分数可定为10，介于这两者之间的情况定为若干中间值，如下表：L分数值事故（事件）发生的可能性10 完全可以预料6 相当可能3 可能，但不经常1 可能性小，完全意外0.5 很不可能，可以设想0.2 极不可能0.1 实际不可能E——暴露于危险环境中频繁程度。

人员出现在危险环境中的时间越多，发生危险性越大。

规定连续出现在危险环境的情况为10，而非常罕见地出现在危险环境中为0.5，介于两者之间的各种情况规定若干个中间值，如下表：E分数值暴漏于危险环境中的频繁程度10 连续暴露6 每天工作时间内暴露3 每周一次，或偶然暴露2 每月一次暴露1 每年几次暴露0.5 非常罕见地暴露C——事故产生的后果。

事故造成人身伤害与财产损失变化范围很大，所以规定分数值在1－100之间。

轻微伤害或较小财产损失的分类规定为1，造成人员伤亡较大的可能性规定为100，其他情况的数值在1－100之间，如下表：C分数值发生事故产生的后果100 大灾难，多人死亡40 灾难，数人死亡15 非常严重，一人死亡7 严重，重伤3 重大，伤残1 引人注目，需要救护D——风险值。

D＝L×E×C，确定D值后关键是如何确定风险级别的界限值，而这个界限值并不是长期固定不变的；在不同时期可根据具体情况确定风险级别的界限值，以确定持续改进的措施。

如下表：D值（=L×E×C）危险程度风险等级>320 及其危险，不能继续作业 A160-320 高度危险，必须立即整改 B70-160 显著危险，需要整改 C20-70 一般危险，需要注意 D<20 稍有危险，可以接受 E。

Lecture 1 The size and role of governmenternment size and its historical development• 3 alternative measures:1.Public spending, expressed as % of GDPa)How much does the government spend?b)Easily available, easy to compare countries.2.Extent of regulation of economic activity by the governmenta)How intrusive is the government?b)Difficult to measure.3.Ownership of firms by the government (SOEs)•In 1870, most people worked in agriculture. Land belongs to noble families. No public health care, little infrastructure・ The parliament was ruled by rich families, who were unwilling to raise taxes, because they would be the one to pay.•The industrial revolution ended the role of land as the primary source. Income tax became significant source of revenue during industry revolution. Capitalists and theemerging middle class began paying taxes. Total revenue was primarily used tofinance wars and national defence.•Summary: Public spending has increased in recent history in many developed countries. Public spending is rising in developing countries.2.Growth of public spending•Wagner^s law: public spending increases proportionally more than the growth of national income.•Wagner^ law is not uniformly true, but is mostly true.•Reasons for Wagner's law:1.Demand for public spending2.Supply for tax revenue3.Political reasons, including extension of the voting franchise2・1・ Demand 一side influencesDemand for public spending increases when governments are assigned responsibilities to achieve social objectives.• Demand for public goodsThe goods supplied by the public sector have a high income elasticity of demand (>1) o Education, Health care.o When people become more well-off, they demand much better education and health care.o If the demand for public goods increases faster than GDP, public spending will rise as a percentage of GDP.•Externalitieso As incomes increase, people become more bothered with negative externalities and the stated has to intervene to regulate certain activities-o Clean water and clean air become important. Resolving externalities associated with public health comes to be understood as important for the quality of life.•Need for regulationIncreased complexity due to economic development imposes new regulations (e・g・financial regulation).•Rising costs of the public goodsThe public sector, for example health care and education, is labor-intensive relative to private sector and therefore cannot substitute easily capital for labor. Since the public sector cannot substitute capita for labor, its cost increases over time.2.2 Supply-side influencesIt became easier to collect taxes•Growth of tax baseo Tax revenue grows when taxation opportunities expand.o In the course of economic growth, people come to have above-subsistence incomes that can be taxed・o Tax bases also expand when people who previously lived a self-sufficient life for themselves and their families through taxable market transactions.•Amenability of people to taxationo Advance in transportation and communication expanded tax revenue for government by allowing people to be taxed who had previously been out ofreach of government tax collector.o The growth of the corporate sector reduced self-employment and increased the proportion of workers for whom employers deducted taxation at source fordelivery to government.o The transactions costs of collecting taxes declined for governments andopportunities for tax evasion declined for taxpayers.2.3 Political influencesDemand for redistribution•In a representative democracy, voters can demand more redistribution by taxing a minority of rich individuals.•When income inequality goes up, the political pressure for redistribution rises, and the government has to increase taxation for high-income people.Ratchet effect•The level of expenditure remains high after the period of upheavalTaxpayers become used to the higher levelPolitically difficult to cut spending, even during recessions3・ Role of government•Time for government to intervene: when three conditions (perfect competition, no externalities and perfect information) are not meet.When these three conditions are not meet, market failure occurs, which justify the existence of the government. Marketfailure is the s让uations in which the market, absent of government intervention,leads to inefficiencies.•Example:Imperfect competitiono Suppose there is a monopoly: Q is below the efficient level QEo The monopolist will cut output to raises prices and maximize profito When markets are not competitive, there is role for government regulation, to restore the efficient level of production.o An anti-monopoly agency of government should ensure that markets are competitiveExternalities:pollutiono Without regulation, pollution would reach excessive levels.o Efficiency requires the government to coordinate individuals and businesses. Public goods: roadso Without government, too few roads would be built.o Efficiency requires public financing of road construction projects.• Additional roleMinimal stateo To prevent anarchy, a society needs:Property rights define the ownership of property and prohibit theft (+other setslaws)丄Enforcement of laws: Enforcement officers and courtso A society also needs defence from outsiders: defence spendingRedistributionEven when the private market outcome is efficient, it may not have gooddistributional properties. Government can intervene to redistribute income through tax and transfer system: social security, public education, health care, unemployment benefits。

HWS-1MZLE/C1智能温湿度控制器说明书一、用途1、适用于室外端子箱，配电箱的自动加热除湿或排风降温或排风除湿，防止端子间爬电引起的各种误动作事故，如：继电器保护端子箱等。

2、适用于开关机构箱内，手车式开关柜，中置柜等设备的箱内对多个部位进行防潮，低温、高温的在线监测。

3、也可用于其他局部需要自动除湿及低温自动加热升温或高温自动排风降温的场合。

二、技术参数1、可实时监控1路温湿度参数2、检测精度：温度±1℃；湿度±5%RH显示分辨率：温度0.1℃; 湿度0.1%RH3、响应时间：小于10秒4、检测范围：湿度： 1~99.9%RH，温度，-19.9~99.9℃5、工作方式：加热器加热或风扇排风出厂默认值：湿度为模式0；当环境湿度大于设置的起始除湿湿度且环境温度抵于20℃时，采取加热除湿策略；当环境湿度大于设置的起始除湿湿度且环境温度高于20℃时，采取强制排风，促进空气对流降低湿度的策略。

此模式能防止配电柜内温度过高造成设备老化；也可通过键盘设置为模式1。

温度：小于5℃，加热继电器触点闭合，大于13℃，加热继电器触点断开；大于40℃，风扇继电器闭合，小于25℃，风扇继电器触点断开。

（也可以根据客户要求在出厂前设置）6、工作电压：220V AC±10%7、功耗：小于3W8、触点性能：可接通5A，可分断250V AC，250V A交流负载一个外接数字传感器同时监测显示温度和湿度，根据设定的参数，控制加热器加热或风扇排风485通信，MODBUS协议有加热器（风扇）断线报警提示功能测量控制温度：-19.9-99.9℃，测量控制湿度： 1-99.9%RH外型尺寸：48×48×100安装方式：嵌入式。

HWS智能温湿度控制器参数设置指南一.按键功能SET键: 1.进入参数设定状态2.存入参数且退出参数设置状态键: 1.使选中的数据位(闪烁)循环右移,或进入下一项菜单2.不存参数,退出参数设置状态.(长时间(大约5秒)按住)↑键:使选中的数据加1↓键:使选中的数据减1二.参数设置流程1)按SET键进入参数设置状态2)在第二行数码管内输入密码789.3)按SET键进入第一项参数(起始加热温度)设置,此时第一排数码管显示“1”4)按键使要设置的相应位处于选中状态(闪烁).按↑健或↓键设置,在本项参数最后一位闪烁时,按键,将进入下一项参数设置.5)重复第4步,直至将所有参数设置完成6)按SET键,存入参数,退出参数设置7)重新给温湿度控制器上电启动三.注意事项:1)每设置一项参数,第一行数码管显示参数号,对应关系如下:1-起始加热温度, 2-停止加热温度, 3-停止排风温度, 4-起始排风温度5-起始加热湿度, 6-停止加热湿度, 7-停止排风湿度, 8-起始排风湿度2)在参数设置过程中,若不需要存入参数而退出参数设置状态,请长时间(大约5秒)按住键,直至退出3)所设置参数必须满足：起始加热温度<停止加热温度<停止排风温度<起始排风温度.起始加热湿度>停止加热湿度>停止排风湿度>起始排风湿度.单片机在存入参数时会自动检查,若错误,会显示矛盾的参数号4)若单片机存入参数正确,数码管会显示“HHHHHH”2秒钟表示正确存入,然后回到正常测量状态.5)若传感器不接或断线,第一排数码管不亮,第二排显示“---”6)出厂时,参数按如下数显起始加热温度:5℃停止加热温度:13℃停止排风温度:25℃起始排风温度:40℃起始加热湿度:88%RH停止加热湿度:78%RH停止排风湿度:55%RH开始排风湿度:35%RH7)设置完参数后务必要重新上电启动智能温湿度控制器通讯规约一、概述：本规约采用Modbus 规约RTU模式1、字节格式：每字节含8位二进制码，传输时加上一个起始位(0)，一个停止位(1)，共10位。