A STOCHASTIC APPROACH FOR CREATING DYNAMIC
CONTEXT-AWARE SERVICES IN SMART HOME
ENVIRONMENT
Hua Si*, Yoshihiro Kawahara*,
Hiroyuki Morikawa?, Tomonori Aoyama*
Abstract
Context-aware service platforms aim at providing users with dynamic services that adapt to changeful environment. Though various toolkits have been developed, it is still not easy for end-users to program their own personalized services. In this paper, we present a context-aware service platform called Synapse that can adequately relate users’ contexts and services, and automatically generate context-aware services based on users’ habits. By exploiting the recorded histories of contexts and services, Synapse can learn different users’ habits. Then Synapse can predict the most relevant services that users will use in current situation based on their habits, and provide services in different modes. As learning and predicting mechanisms are on the basis of a stochastic approach – Bayesian Networks [5], Synapse can absorb various uncertainties arising from sensor data and provide truly personalized services.
1. Introduction
Context-awareness is now regarded as a key ingredient for pervasive computing, and several toolkits such as Context Toolkit [8] and Location Stack [2] have been proposed to incorporate users’ contexts into network applications. A category of attractive context-aware applications is desired in indoor environments such as home and office [5]. In such an environment, dynamic services enabled by the seamless integration of sensors, home appliances and networks will not only give great helps to the elders and patients, but also facilitate the daily life of ordinary people. Some prior projects focused on recognizing the contexts, such as users’ activities and environmental conditions, from a large number of simple sensors [10]. Some other projects propose ECA Rule that allows application developers to specify and associate events with actions in a rule-specification language [3]. However, these works are not really easy for end-users to program their own personalized services. Therefore, a dynamic mechanism that can automatically generate context-aware services based on the users’ habits is necessary. We are developing a context-aware service platform called Synapse, which can learn different users’ habits by exploiting the recorded histories of contexts and services, and then predict and provide the most relevant services that users will use in current situation based on their habits.
The following “daily scenarios” are learned and implemented in a smart home test bed of Synapse: x The “Light” scenario: if it is too dark in the room, Synapse will automatically turn on the light. x The “TV” scenario: Synapse will recommend TV programs appropriate for people in living room. (When only kids are watching TV, cartoon program will be recommended. When parents * Department of Information and Communication Engineering, The University of Tokyo
? Department of Frontier Informatics, The University of Tokyo
and kids are watching TV together, movies or some other programs will be recommended on the basis of user’s favour.)
x The “Music” scenario: Synapse will automatically turn down the volume of music player when someone is using the phone, and turn up the volume after using the phone.
Our basic assumption of this system is that a user may repeatedly choose preferred services in similar situations, which are his habits. Obviously, the best grounds for learning users’ habits exist in the recorded histories of services used by users and the contexts (we call “sensor events” in Synapse), which indicate the situations in which each service is used. Considering the complexity of human habits and the flexibility of the system, we choose one of Bayesian Networks [6], HMM (Hidden Markov Model) [7] to build the stochastic model of Synapse. This model consists of continuous cycles, and each cycle is composed of two phases: the Learning Phase and the Executing Phase. Firstly in a Learning Phase, Synapse learns the relationships between sensor events and services by exploiting recorded histories of them. Then in Executing Phase, based on the learned relationships and the current sensor events, Synapse predicts the most possible services to be used and provides them to users. Since users would like to enjoy the autonomous services in a moderate degree without losing control of them [1], Synapse provides services in two modes: Active Mode will start a service automatically, where Passive Mode recommends the top 3 relevant services in a list and let users select as they wish. The results of the Learning Phase are used as the prior knowledge for the next cycle. To easily achieve the personalization, the user ID is treated as a sensor event.
We will discuss the architecture and implementation details of Synapse test bed in section 2. The conclusions will be given in section 3.
2. Architecture and Implementation of Synapse
The test bed of Synapse consists of four parts: 1) the Synapse Core, 2) the sensors capturing real world information, 3) the home appliances providing services, and 4) the web user interface, as shown in Figure 1.
2.1. Synapse Core
We use HMM to model the relationships between sensor events and services. As shown in Figure 2, there are two basic components in HMM: the hidden states X t and the observations of states Y t. In Synapse, each hidden state X t corresponds to a service S t*, to indicate the situation in which this service is used, and the observation is a vector of sensor events E? extracted from sensor data. In a Learning Phase (t=1, 2...T), we use forwards-backwards algorithm and EM (expectation maximization) algorithm to learn the parameters of the model (?(i), A(i,j), P(Y t|X t))?. After that, in an Executing Phase (t>T), we use the learned parameters and new sensor events to compute the occurrence probability of each service through a filtering algorithm and sort them. If a probability is higher than a threshold, the corresponding service will automatically start in Active Mode. The top 3 services will be recommended in a list to the user interface in Passive Mode. All these algorithms are implemented on Matlab.
* S (SN, ST): SN - service ID, ST - the time this service is recorded.
? E (EN, EV, ET): EN - event ID, EV - value of event, ET - the time this event is recorded.
?(i)=P(X
=i) is the prior probability of HMM. A(i,j)=P(X t=j|X t-1=i) is the transition matrix of HMM. P(Y t|X t) is the
1
observation model of HMM.
2.2. Sensor Event Collection Part
Sensor event collection part captures the real world information via various sensors, converts raw data into useful contexts (we call “sensor events” in Synapse), and records these sensor events in database. Sensor Aggregator fuses the raw sensor data and reduces the noise. For instance, the average temperature in a room is fused from different temperature sensors. Context Inference extracts the complex events such as “the user is sleeping” from simple events. In this test bed, 4 kinds of sensors are used to produce 11 sensor events: RFID is used to identify Users, U 3 [4] nodes are used to capture the temperature, brightness and human motion, a contact detector detects
Sensor Event
Fig. 1. Architecture of Synapse. Sensors are on the left, and services are on the right.
Fig. 2. Model of Synapse. The grey rectangles indicate a certain interval before ST. 2.3. Service Control Part
Service control part controls various home appliances to supply services. Service Launcher operates as a proxy between Synapse Core and the home appliances. It receives the service ID from Synapse Core through UDP/IP networks, and controls the home appliance corresponding to this service ID. It also sends the ID of a selected service to Synapse Core for history-recording. As a result, the scalability is ensured, since Synapse Core can manage the services only with IDs, and ignore the various operations of home appliances. In this test bed, 4 home appliances are used to provide 23 services: a light and a fan provide on/off services, a TV provides on/off, 12 channels and 2 videos, and a music player provides on/off and music mute/loud services.
2.4. User Interface
Synapse provides a user interface in HTML form on Matlab Web Server. Users can browse this webpage through PC, PDA, or cellular phone, and start a service only by selecting this service ID. The recommended service list on this website can automatically update after a fixed interval, or be manually updated.
3. Conclusions
In this paper, we presented a general context-aware service platform—Synapse. By exploiting the recorded histories of contexts and services, Synapse can learn the users’ habits. After that, Synapse can predict the most relevant services that users will use in current situation based on their habits, and provide services in Active Mode and Passive Mode. We also described the architecture and implementation details of a smart home test bed of Synapse. The initial performance evaluation of Synapse can be found in [9]. In the future, we will extend the sensor and service parts of our test bed and build a whole Synapse system in a real house, and put the system under real inhabitants’ tests.
4. References
[1] BARKHUUS, L., Is Context-Aware Computing Taking Control Away from the User?Three Levels of Interactivity Examined, in: Proceedings of Ubicomp 2003, LNCS 2864, (2003).
[2] GRAUMANN, D., Real-world implementation of the location stack: The universal location framework, in: Proceedings of WMCSA 2003, (2003), 122–128.
[3] IPINA, D. L., An ECA Rule-Matching Service for Simpler Development of Reactive Applications, in: IEEE Distributed Systems, Vol. 2, (2001).
[4] KAWAHARA, Y., Design and Implementation of a Sensor Network Node for Ubiquitous Computing Environment, in: Proceedings of IEEE Semiannual Vehicular Technology Conference, 2003.
[5] MEYER, S., A survey of research on context-aware homes, in: Proceedings of the Australasian information security workshop conference on ACSW frontiers, Vol. 21, (2003).
[6] MURPHY, K., Dynamic Bayesian Networks: Representation, Inference and Learning, PhD Dissertation, UC Berkeley (2002).
[7] RABINER, L. R., A tutorial on Hidden Markov Models and selected applications in speech recognition, in: Proceedings of the IEEE, (1989), 77(2):257–286.
[8] SALBER, D., The context toolkit: Aiding the development of context-enabled applications, Technical report, Georgia Institute of Technology (2000).
[9] SI, H., Performance Evaluation of a Context-aware Service Platform Synapse, in: Proceedings of IEICE General Conference, Osaka, Japan, (2005).
[10] TAPIA, E. M., Activity Recognition in the Home Using Simple and Ubiquitous Sensors, in: Proceedings of Pervasive 2004, LNCS 3001, (2004), 158-175.
AN EXCITING JOB I have the greatest job in the world. I travel to unusual places and work alongside people from all over the world. Sometimes working outdoors, sometimes in an office, sometimes using scientific equipment and sometimes meeting local people and tourists, I am never bored. Although my job is occasionally dangerous, I don't mind because danger excites me and makes me feel alive. However, the most important thing about my job is that I help protect ordinary people from one of the most powerful forces on earth - the volcano. I was appointed as a volcanologist working for the Hawaiian V olcano Observatory (HVO) twenty years ago. My job is collecting information for a database about Mount Kilauea, which is one of the most active volcanoes in Hawaii. Having collected and evaluated the information, I help other scientists to predict where lava from the volcano will flow next and how fast. Our work has saved many lives because people in the path of the lava can be warned to leave their houses. Unfortunately, we cannot move their homes out of the way, and many houses have been covered with lava or burned to the ground. When boiling rock erupts from a volcano and crashes back to earth, it causes less damage than you might imagine. This is because no one lives near the top of Mount Kilauea, where the rocks fall. The lava that flows slowly like a wave down the mountain causes far more damage because it
八年级下学期全部长篇课文 Unit 1 3a P6 In ten years , I think I'll be a reporter . I'll live in Shanghai, because I went to Shanfhai last year and fell in love with it. I think it's really a beautiful city . As a reporter, I think I will meet lots of interesting people. I think I'll live in an apartment with my best friends, because I don' like living alone. I'll have pets. I can't have an pets now because my mother hates them, and our apartment is too small . So in ten yers I'll have mny different pets. I might even keep a pet parrot!I'll probably go skating and swimming every day. During the week I'll look smart, and probably will wear a suit. On the weekend , I'll be able to dress more casully. I think I'll go to Hong Kong vacation , and one day I might even visit Australia. P8 Do you think you will have your own robot In some science fiction movies, people in the future have their own robots. These robots are just like humans. They help with the housework and do most unpleasant jobs. Some scientists believe that there will be such robots in the future. However, they agree it may take hundreds of years. Scientist ae now trying to make robots look like people and do the same things as us. Janpanese companies have already made robts walk and dance. This kond of roots will also be fun to watch. But robot scientist James White disagrees. He thinks that it will be difficult fo a robot to do the same rhings as a person. For example, it's easy for a child to wake up and know where he or she is. Mr White thinks that robots won't be able to do this. But other scientists disagree. They think thast robots will be able t walk to people in 25 to 50tars. Robots scientists are not just trying to make robots look like people . For example, there are already robots working in factories . These robots look more like huge arms. They do simple jobs over and over again. People would not like to do such as jobs and would get bored. But robots will never bored. In the futhre, there will be more robots everwhere, and humans will have less work to do. New robots will have different shapes. Some will look like humans, and others might look like snakes. After an earthquake, a snake robot could help look for people under buildings. That may not seem possibe now, but computers, space rockets and even electric toothbrushes seemed
高中英语选修 6 Unit 1 A SHORT HISTORY OF WESTERN PAINTING Art is influenced by the customs and faith of a people. Styles in Western art have changed many times. As there are so many different styles of Western art, it would be impossible to describe all of them in such a short text. Consequently, this text will describe only the most important ones. Starting from the sixth century AD. The Middle Ages(5th to the 15th century AD) During the Middle Ages, the main aim of painters was to represent religious themes. A conventional artistof this period was not interested in showing nature and people as they really were. A typical picture at this time was full of religious symbols, which created a feeling of respect and love for God. But it was evident that ideas were changing in the 13th century when painters like Giotto di Bondone began to paint religious scenes in a more realistic way. The Renaissance(15th to 16th century) During the Renaissance, new ideas and values gradually replaced those held in the Middle Ages. People began to concentrate less on
英语选修六课文翻译 第五单元
英语选修六课文翻译第五单元 reading An exciting job I have the greatest job in the world. travel to unusual places and work alongside people from all over the world sometimes working outdoors sometimes in an office sometimes using scientific equipment and sometimes meeting local people and tourists I am never bored although my job is occasionally dangerous I don't mind because danger excites me and makes me feel alive However the most important thing about my job is that I heIp protect ordinary people from one of the most powerful forces on earth-the volcano. I was appointed as a volcanologist working for the Hawaiian Volcano Observatory (HVO) twenty years ago My job is collecting information for a database about Mount KiLauea which is one of the most active volcanoes in Hawaii Having collected and evaluated the information I help oyher scientists to predict where lava from the path of the lava can be warned to leave their houses Unfortunately we cannot move their homes out of the way and many houses have been covered with lava or burned to the ground. When boiling rock erupts from a volcano and crashes back to earth, it causes less damage than you might imagine. This is because no one lives near the top of Mount Kilauea, where the rocks fall. The lava that flows slowly like a wave down the mountain causes far more damage because it buries everything in its path under the molten rock. However, the eruption itself is really exciting to watch and I shall never forget my first sight of one. It was in the second week after I arrived in Hawaii. Having worked hard all day, I went to bed early. I was fast asleep when suddenly my bed began shaking and I heard a strange sound, like a railway train passing my window. Having experienced quite a few earthquakes in Hawaii already, I didn't take much notice. I was about to go back to sleep when suddenly my bedroom became as bright as day. I ran out of the house into the back garden where I could see Mount Kilauea in the distance. There had been an eruption from the side of the mountain and red hot lava was fountaining hundreds of metres into the air. It was an absolutely fantastic sight. The day after this eruption I was lucky enough to have a much closer look at it. Two other scientists and I were driven up the mountain and dropped as close as possible to the crater that had been formed duing the eruption. Having earlier collected special clothes from the observatory, we put them on before we went any closer. All three of us looked like spacemen. We had white protective suits that covered our whole body, helmets,big boots and special gloves. It was not easy to walk in these suits, but we slowly made our way to the edge of the crater and looked down into the red, boiling centre. The other two climbed down into the crater to collect some lava for later study, but this being my first experience, I stayed at the top and watched them.
高二英语教学设计 Book6 Unit 5 Reading An Exciting Job 1.教学目标（Teaching Goals）: a. To know how to read some words and phrases. b. To grasp and remember the detailed information of the reading material . c. To understand the general idea of the passage. d. To develop some basic reading skills. 2.教学重难点: a.. To understand the general idea of the passage. b. To develop some basic reading skills. Step I Lead-in and Pre-reading Let’s share a movie T: What’s happened in the movie? S: A volcano was erupting. All of them felt frightened/surprised/astonished/scared…… T: What do you think of volcano eruption and what can we do about it? S: A volcano eruption can do great damage to human beings. It seems that we human beings are powerless in front of these natural forces. But it can be predicted and damage can be reduced. T: Who will do this kind of job and what do you think of the job? S: volcanologist. It’s dangerous. T: I think it’s exciting. Ok, this class, let’s learn An Exciting Job. At first, I want to show you the goals of this class Step ⅡPre-reading Let the students take out their papers and check them in groups, and then write their answers on the blackboard (Self-learning) some words and phrases：volcano, erupt, alongside, appoint, equipment, volcanologist, database, evaluate, excite, fantastic, fountain, absolutely, unfortunately, potential, be compared with..., protect...from..., be appointed as, burn to the ground, be about to do sth., make one’s way. Check their answers and then let them lead the reading. Step III Fast-reading 这是一篇记叙文，一位火山学家的自述。作者首先介绍了他的工作性质，说明他热爱该项工作的主要原因是能帮助人们免遭火山袭击。然后，作者介绍了和另外二位科学家一道来到火山口的经历。最后，作者表达了他对自己工作的热情。许多年后，火山对他的吸引力依然不减。 Skimming Ⅰ.Read the passage and answer: (Group4) 1. Does the writer like his job?( Yes.) 2. Where is Mount Kilauea? (It is in Hawaii) 3. What is the volcanologist wearing when getting close to the crater? (He is wearing white protective suits that covered his whole body, helmets, big boots and
Unit5 Reading An Exciting Job 说课稿 Liu Baowei Part 1 My understanding of this lesson The analysis of the teaching material:This lesson is a reading passage. It plays a very important part in the English teaching of this unit. It tells us the writer’s exciting job as a volcanologist. From studying the passage, students can know the basic knowledge of volcano, and enjoy the occupation as a volcanologist. So here are my teaching goals: volcanologist 1. Ability goal: Enable the students to learn about the powerful natural force-volcano and the work as a volcanologist. 2. Learning ability goal: Help the students learn how to analyze the way the writer describes his exciting job. 3. Emotional goal: Make the Students love the nature and love their jobs. Learn how to express fear and anxiety Teaching important points: sentence structures 1. I was about to go back to sleep when suddenly my bedroom became as bright as day. 2. Having studied volcanoes now for more than twenty years, I am still amazed at their beauty as well as their potential to cause great damage. Teaching difficult points: 1. Use your own words to retell the text. 2. Discuss the natural disasters and their love to future jobs. Something about the S tudents: 1. The Students have known something about volcano but they don’t know the detailed information. 2. They are lack of vocabulary. 3. They don’t often use English to express themselves and communicate with others.
我的工作是世界上最伟大的工作。我跑的地方是稀罕奇特的地方，我见到的是世界各地有趣味的人们，有时在室外工作，有时在办公室里，有时工作中要用科学仪器，有时要会见当地百姓和旅游人士。但是我从不感到厌烦。虽然我的工作偶尔也有危险，但是我并不在乎，因为危险能激励我，使我感到有活力。然而，最重要的是，通过我的工作能保护人们免遭世界最大的自然威力之一，也就是火山的威胁。 我是一名火山学家，在夏威夷火山观测站（HVO）工作。我的主要任务是收集有关基拉韦厄火山的信息，这是夏威夷最活跃的火山之一。收集和评估了这些信息之后，我就帮助其他科学家一起预测下次火山熔岩将往何处流，流速是多少。我们的工作拯救了许多人的生命，因为熔岩要流经之地，老百姓都可以得到离开家园的通知。遗憾的是，我们不可能把他们的家搬离岩浆流过的地方，因此，许多房屋被熔岩淹没，或者焚烧殆尽。当滚烫沸腾的岩石从火山喷发出来并撞回地面时，它所造成的损失比想象的要小些，这是因为在岩石下落的基拉韦厄火山顶附近无人居住。而顺着山坡下流的火山熔岩造成的损失却大得多，这是因为火山岩浆所流经的地方，一切东西都被掩埋在熔岩下面了。然而火山喷发本身的确是很壮观的，我永远也忘不了我第一次看见火山喷发时的情景。那是在我到达夏威夷后的第二个星期。那天辛辛苦苦地干了一整天，我很早就上床睡觉。我在熟睡中突然感到床铺在摇晃，接着我听到一阵奇怪的声音，就好像一列火车从我的窗外行驶一样。因为我在夏威夷曾经经历过多次地震，所以对这种声音我并不在意。我刚要再睡，突然我的卧室亮如白昼。我赶紧跑出房间，来到后花园，在那儿我能远远地看见基拉韦厄火山。在山坡上，火山爆发了，红色发烫的岩浆像喷泉一样，朝天上喷射达几百米高。真是绝妙的奇景！ 就在这次火山喷发的第二天，我有幸做了一次近距离的观察。我和另外两位科学被送到山顶，在离火山爆发期间形成的火山口最靠近的地方才下车。早先从观测站出发时，就带了一些特制的安全服，于是我们穿上安全服再走近火山口。我们三个人看上去就像宇航员一样，我们都穿着白色的防护服遮住全身，戴上了头盔和特别的手套，还穿了一双大靴子。穿着这些衣服走起路来实在不容易，但我们还是缓缓往火山口的边缘走去，并且向下看到了红红的沸腾的中心。另外，两人攀下火山口，去收集供日后研究用的岩浆，我是第一次经历这样的事，所以留在山顶上观察他们
英语选修六课文翻译第五单元 reading An exciting job I have the greatest job in the world. travel to unusual places and work alongside people from all over the world sometimes working outdoors sometimes in an office sometimes using scientific equipment and sometimes meeting local people and tourists I am never bored although my job is occasionally dangerous I don't mind because danger excites me and makes me feel alive However the most important thing about my job is that I heIp protect ordinary people from one of the most powerful forces on earth-the volcano. I was appointed as a volcanologist working for the Hawaiian Volcano Observatory (HVO) twenty years ago My job is collecting information for a database about Mount KiLauea which is one of the most active volcanoes in Hawaii Having collected and evaluated the information I help oyher scientists to predict where lava from the path of the lava can be warned to leave their houses
新目标英语七年级下册课文Unit04 Coverstion1 A: What does your father do? B: He＇s a reporter. A:Really?That sounds interesting. Coverstion2 A:What does your mother do,Ken? B:She＇s a doctor. A:Really?I want to be a doctor. Coverstion3 A:What does your cousin do? B:You mean my cousin,Mike? A:Yeah,Mike.What does he do? B:He is as shop assistant. 2a,2b Coverstion1 A: Anna,doesyour mother work? B:Yes,she does .She has a new job. A:what does she do? B: Well ,she is as bank clerk,but she wants to be a policewoman. Coverstion2 A:Is that your father here ,Tony?
B:No,he isn't .He's working. B:But it's Saturday night.What does he do? B:He's a waiter Saturday is busy for him. A:Does he like it? B:Yes ,but he really wants to be an actor. Coverstion3 A:Susan,Is that your brother? B:Yes.it is A:What does he do? B:He's a student.He wants to be a doctor. section B , 2a,2b Jenny:So,Betty.what does yor father do? Betty: He's a policeman. Jenny:Do you want to be a policewoman? Betty:Oh,yes.Sometimes it's a little dangerous ,but it's also an exciting job.Jenny, your father is a bank clerk ,right? Jenny:Yes ,he is . Sam:Do you want to be a bank clerk,too? Jenny:No,not really.I want to be a reporter. Sam: Oh,yeah?Why? Jenny:It's very busy,but it's also fun.You meet so many interesting people.What about your father ,Sam. Sam: He's a reporter at the TV station.It's an exciting job,but it's also very difficult.He always has a lot of new things to learn.Iwant to be a reporter ,too
人教版选修Unit 5 The power of nature阅读课教学设计 Learning aims Knowledge aims: Master the useful words and expressions related to the text. Ability aims: Learn about some disasters that are caused by natural forces, how people feel in dangerous situations. Emotion aims: Learn the ways in which humans protect themselves from natural disasters. Step1 Leading-in 1.Where would you like to spend your holiday? 2.What about a volcano? 3.What about doing such dangerous work as part of your job ? https://www.doczj.com/doc/7d10118120.html, every part of a volcano. Ash cloud/volcanic ash/ Crater/ Lava /Magma chamber 【设计意图】通过图片激发学生兴趣，引出本单元的话题，要求学生通过讨论, 了解火山基本信息，引出火山文化背景，为后面的阅读做铺垫。利用头脑风暴法收集学生对课文内容的预测并板书下来。文内容进行预测，培养学生预测阅读内容的能力。同时通过预测激起进一步探究 Step2. Skimming What’s the main topic of the article?
Unit1 SectionA 1a Canada, France ,Japan ,the United States ,Australia, Singapore ,the United Kingdom,China 1b Boy1:Where is you pen pal from,Mike? Boy2:He's from Canada. Boy1:Really?My pen pal's from Australia.How about you,Lily?Where's your pen pal from? Girl1:She's from Japan.Where is Tony's pen pal from? Gril2:I think she's from Singapore. 2b 2c Conversation1 A: Where's you pen pal from, John? B: He's from Japan, A:Oh,really?Where does he live? B: Tokyo. Conversation2 A: Where's your pen pal from, Jodie? B: She's from France. A: Oh, she lives in Pairs. Conversation3 A: Andrew, where's your pen pal from? B: She's from France. A: Uh-huh. Where does she live? B: Oh, She lives in Paris.