Experiment 4
Contents
1. will provide an initial state transition diagram Upload this diagram 4 2 2 Experience the Passenger Functions Request Rights Pass Rights 4 2 3 Experience the Passenger Functions Intermediate Call IC Accept Reject IC 4 2 4 Experience the Passenger Functions Call Tutor CT 4 2 5 Discuss your experiences and update the given state transition diagram Store different versions to save intermediate results Print the final version of the State transition diagram and attach it to this manual 4 2 6 Repeat tasks 4 2 2 4 2 3 and 4 2 4 and notice how the colours of your communication windows are affected by these functions _13 4 2 Fill in the following table in which you have to associate every window background colour with the roles of the Passenger participants Color of the Color of the name label buttons to request the Floor 142. University Duisburg Essen Faculty of Engineering Computer Engineering Dr Ing Stefan Werner LAB CSCW amp SOFTWARE ENGINEERING EXPERIMENT 4 Desktop Conferences First Name Group Number As preparation to this experiment e Study the research papers given so far as appendix to lab 1 2 3 e Study this manual e All questions in section 3 marked with are to be answered as preparation for the experiment Please write the solutions into the designated fields as far as given and bring them to the practical During the experiment e Answer all questions in the Hands on section After the experiment e Please fill in the questionnaire distributed by the tutors 1 Introduction 1 1 Desktop Conferencing systems Conferencing systems cover a wide range of interaction between team members They range from computer conferences to video and desktop conferences As Videoconferencing has been experienced through lab 3 lab 4 focuses more on desktop conferencing systems Desktop conferencing is a combination of real time computer conferencing and teleconferencing Normally people involved in desktop conferences are distributed across several meeting rooms Between these meeting rooms there is an audio link and for the transfer of gestures in case of desktop video conferencing also a video connection In addition to audio and video connections desktop conferencing uses personal computers which support shared applica
3. cribe the differences between the options request rights intermediate call and call tutor in the context of the synchronous groupware PASSENGER 11 4 Hands On e In this hands on part of the experiment students shall gain experiences in the usage of desktop conferencing tools by the example of the synchronous groupware PASSENGER 4 1 Setting up a Passenger Environment 4 1 1 Set up a PASSENGER session and connect to it Describe the single steps and the information required to do so 4 1 2 Logout and try to login to other Passenger sessions Explain why you cannot 4 1 3 Try to change the size of your own communication window and also the sizes of the communication windows of your other participants Try to cover any communication window with other elements icons from your desktop Explain the result 4 1 4 Each participate shall notice the order of how participants including yourself appear on the screen Discuss the result via PASSENGER 4 2 Behavior of the synchronous groupware PASSENGER Now Students shall analyze the behavior of PASSENGER in case a team works commonly on a software design Therefore the overall task is to model the behavior of the synchronous groupware PASSENGER as a state transition diagram The tutors will provide an initial model which the groups shall finish during the experiment Perform the following tasks and continuously update that model 4 2 1 The tutors
4. ct only The Private windows is used to edit the artifact offline If you have the rights everything is shown to the other ones in the Public window 3 1 2 ee Edit functions Figure 16 Standard Windows function cut copy paste and delete Switch telepointer on off If you have the rights your Windows mousepointer is mirrored to the others Public window as a green mouse pointer if you move the mouse over the Private window Transfer the common artifact to the Private window to explain use telepointer and or edit it If you have the rights your Private window is mirrored to the others Public window Your Public window keeps unchanged Now it is up to you You can a Work with your currently displayed document b Load a document from the Local Global History see below c Continue with the last common document In this case you can copy the document from your unchanged Public window to your Private window anytime Deselect all the other buttons Just move objects in the Private windows Normal mode Clear the Private window to start a new document UNDO and REDO buttons Currently you can just Undo Redo one step Print c
5. d several methods of data transfer have been implemented TCP based unicast connections for reliable client server communications and UDP based unreliable multicast connections are implemented as interclient communications Comparing the professional field in software engineering with software engineering education the following aspects have to be put into consideration Working in a team dividing up the given task into subtasks discussing provisional results and integrating first results afterwards already require discipline of the students without using groupware The usage of videoconference techniques also requires that students work in a completely new scenario Thus interface design and group awareness support obtains an outstanding meaning The PASSENGER user interface contains of video screens of each member and a CASE tool in a public window for the common process of the outline documents Figure 1 shows the PASSENGER user interface of the client software Figure 1 PASSENGER Client User Interface Each member has the same view of the public window according to the WYSIWIS principle but only one of them can alter the document at a certain time A telepointer serves to elucidate and to present facts The access to the public window is controlled by a floor control The design of the floor control is based on an analysis of the group processes during traditional software engineering labs It aims at maximizing the fairness t
6. eo Options Windows E Ei Pad Fel Ed gogg Fal Figure 8 2 4 Floor Control There are 4 video screens as maximum for a screen with a resolution of 1024x768 pixels The local video screen is always the first left and the tutor video screen is always the last right In case that you are the tutor the first rule has priority There are 4 buttons and a pop up menu to interact with the other participants Request rights Pass fights Intermediate call Call tukor Figure 9 a Request rights Only the one who has the rights can talk to the others and modify the common artifact If no one has the rights you will get them immediately F Passenger Client Casetool AM File Video Options Windows Figure 10 If not the rights are passed in the order the requests were received For example UserA requests the rights green raised hand but UserB has the rights green bar If UserB pass them the UserA will get them G Passenger Client Casetool A File video Options Windows Figure 11 b Pass rights If you have the rights you can pass them to the next one see Figure 10 blue hand pointing to the right If there is no next one nobody has the rights c Intermediate call If you have a question or comment which has to be discussed immediately you can use this button The one who has the rights must commit your request and passes the rights directly to you Af
7. next two clients who requested the floor Important is that the list never shows two equal entries Thus two members cannot exclude the third person from the discussion Further more a member can ask to interrupt the actual floor holder This is done by sending an intermediate call to the actual floor holder Apart from this the tutor can be called by any user at any time Therefore the model serves all of the above formulated requirements regarding fairness Data exchange between clients and server require a reliable service In the internet such a service is made available by the TCP The exchange of multimedia data audio video does not compellingly require a reliable service and can principally be conducted over UDP based services For this a direct data exchange between the clients involved is selected Data exchange can take place alternatively via multi unicast or native multicast For future oriented reasons and the flexibility in relation to extensions and the integration of new services IP protocols version 6 are supported Figure 2 represents the implementations for data exchange For a better overview only three clients are represented Server reliable unicast service Client 1 Client 3 Client 2 Figure 2 Client Server Architecture of synchronous groupware Passenger 2 PASSENGER Client User Manual 2 1 Network configuration Go to menu gt Options gt Network Settings or press the hotkey F4 Passenger Client Case
8. owards the access to the floor and in supporting the students in their discussion behavior Each member is also equipped with a private window for trying out ideas A chat window was implemented so the conference can be ended simultaneously in case of bad transfer circumstances Concerning group awareness and the setup of partner images and relationship aspects the following design and implementation steps are taken into account each member is represented in an individual video screen the members are always shown in the same video screen the video screens can not be changed in either size or position none of the video screens can be covered up by another window the video screen of the person who has access to the shared resources is always highlighted e the CASE tool contains a global and local history of changes The floor control is implemented on the server side and handles the access to the floor and the shared resources Furthermore it coordinates the course of communication through an administration of different kinds of permissions e g permissions to speak permissions to alter the documents Floor control approaches usually are mainly technically or social oriented The PASSENGER approach combines the advantages of technical and social floor passing methods An essential part of the floor control implementation is the permission list This list can have three possible entries The actual floor holder is followed by the
9. ter passing the rights back the normal chain of requests is processed again Passenger Client Casetool kr File Video Options Windows Figure 12 d Call tutor In a normal situation the tutor user is not needed If you think you need help from the tutor press this button Your video screen is mark the tutor s blackboard is yellow now If the tutor requests the rights the normal chain of requests is cleared and the tutor gets the rights immediately Figure 13 2 5 Selecting a Tool Go to menu gt Windows and seleted a tool as displayed below Currently there are just two tools but the number can increase cae Passenger Client Casetool File video Options windows Casetool Figure 14 2 6 The CASE Tool The Computer Aided Software Engieneering Tool is seperated into 4 areas 1 Symbols to create a Ward amp Mellor diagram 2 The Workspace 3 Standard edit functions 4 History Passenger Client Casetool laj x sr File Wideo Options Windows e x 1 Datatrans AAOPUI A WRAL aiqeppa AO Seog Local Histoy History tdiaoran 01052002 17 04 39 D z 5 a fa 2 Auo Aala Disconnect Ls waiting Mic off Figure 15 1 The symbols are not explained here 2 The Workspace is splitted into the Public window and the Private window The Public window is used to display the common artifa
10. tions thus enabling joint manipulation of common electronic information The video images are integrated into a screen window The major focus lies on the integration of the work environments of the geographically dispersed group members rather than on the display of the videos of the group members on the screen For communication between audio video and data a multimedia network is used 1 2 PASSENGER a synchronous groupware for desktop conferences Modern software engineering in any case signifies team work The world wide extension of the data networks and the continuing globalization add another component to software engineering the development in worldwide distributed teams The usage of this forward looking work form in university education can render a special contribution to future and practice operations of students Thus a synchronous groupware named PASSENGER was developed at the University of Duisburg Essen throughout the last years The synchronous groupware PASSENGER can support synchronous meetings with up to four members It provides video and audio channels for communication purposes a floor control mechanism to support the course of discussion and several measures for carrying out group awareness information as explained in the following The overall PASSENGER concept sees Windows based systems as its target platform and the global internet as its transport medium It is implemented as a client server architecture an
11. tool A File wideo Windows 7 york Settings i ae Video Settings Show Permissions Hint Local History i Figure 3 Enter a valid IPv4 address for the Passenger Server and a valid control port 1111 is a default value Netsettings x Serveraddress 1 F COo Ret Controlport fi 111 Cancel Figure 4 2 2 Login to the Passenger Server Go to menu gt File gt Login or press the hotkey F5 Passenger Client Casetool OF Fie video Options Windows 7 Figure 5 Enter username and password as configured by the Passenger Administrator This as nothing to do the NT Authorization Enter Username lu send Enter Password oo Cancel Figure 6 It takes 3 seconds to check the uniqueness of the new multicast address if necessary After login the screen should look like this Vr aa Pa eS r A bn a a i gt D A ede Lo l Ei 6 4 i i _ _ any i Fi ay r ibe Pil Ea tel Passenger Client Casetool GJ File video Options Windows TCESENE i Al Md Fal Ed 7 HHUA no oa Figure 7 2 3 Start video capture and data stream Go to menu gt Tool gt Send Video or press the hotkey F3 Activating the transmission of video data automatically starts capturing Passenger uses the last used settings made by the software which comes with your camera If there is no picture check the settings with this software AB Fie vid
12. urrectly displayed workspace to a printer or make a bitmap copy into the clipboard e g to paste it into a Word Document The history is splitted into the Local histroy and the Global histroy The Local histroy is a list of CASE Tool Files saved to the workstation s harddrive The Global history is a list of CASE Tool Files saved to the server s harddrive A file from the Global history can be downloaded into the Private window by doubleclicking the list A local file can be uploaded to the server or can be deleted with a popupmenu Lo cal History Global Histor passin par na Lontestosorar plead ee Saver Delete Figure 17 3 Preparation Please prepare the following questions as preparation for your experiment Write down the notes in the fields given below the questions if not announced different in the task 3 1 4 Distinguish between Real Time Computer Conferencing Teleconferencing and Desktop Conferencing 3 2 What isa role in the context of a desktop conference 3 3 Describe the terms whiteboard shared context public window and private window in the context of the synchronous groupware PASSENGER 10 3 4 How is group awareness implemented in the context of the synchronous groupware PASSENGERr 3 5 How is Floor Control implemented in thecontext of the synchronous groupware PASSENGER 3 6 Des
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