Collaborative Surgical Simulation Over the Internet

Collaborative Surgical Simulation over the Medicine on the Net Internet Co-Surgeon combines 3D surgery simulation with CSCW technology to enable surgeons to collaboratively simulate alternative treatment plans over the Internet.

s the medical field becomes more work together on a complete and accurate Yeongho Kim,Jeong-Ho specialized, the need for coopera- operation plan — from initial diagnosis to Choi, Jongki Lee, Ation among medical personnel — final treatment. Several medical image sys- and Myeng Ki Kim both across and within specialties — tems, such as CyberMed’s V-works and Seoul National University increases. A major obstacle to achieving Virtual Reality Surgical Planning (VRSP),1 this cooperation is the distance that often have recently been used in surgical simu- Nam Kuk Kim separates specialists. Telemedicine promis- lations on 3D models. Almost all systems CyberMed es to dramatically change the medical that provide 3D surgical simulation, how- environment by allowing specialists to col- ever, are intended for single, standalone Jin Sup Yeom laborate across great distances. Computer- users. If such surgical simulation systems Eulji Medical University Hospital supported cooperative work (CSCW) — a could be interconnected via the Internet, key component of telemedicine — has been multiple specialists and possibly patients Yong Oock Kim applied where interdisciplinary coopera- could work together on the treatment plan. Yonsei University tion of health-care personnel is needed to Co-Surgeon is an Internet-based tele- provide high-quality medical services (see simulation surgery system. The system the sidebar, “CSCW and Medical Imaging”, combines 3D surgery simulation with for some recent developments in this area). CSCW technology to enable multiple users One area where telemedicine can be in remote locations to manipulate 3D used to improve quality of care is in simu- anatomical models and simulate surgical lating surgical procedures. Such simulation operations while sharing a view of the sim- lets surgeons create more precise operation ulation. In addition, the system can store plans. Consider, for example, corrective the simulated procedure so that offline surgery of a facial deformity. The com- users can later replay it and participate plexity of the anatomical structures and the asynchronously. Co-Surgeon can also importance of the resulting aesthetics manage the procedures, facilitating the use makes this a difficult operation, and it of the simulation capability and widening often requires several related specialists to the system’s application in surgical educa-

CSCW and Medical Imaging

Most conventional medical imaging systems tems support diagnosis, treatment planning, 3. A. Rovetta,“Computer Assisted Surgery with 3D provide ﬁlm-based 2D environments.The and education.Virtual endoscopy systems Robot Models and Visualisation of the Telesurgical introduction of picture archiving and com- such as virtual bronchoscopy8 and Action,” Studies in Health Technology and Informat- munication systems (PACSs) allowed med- angioscopy9 provide an environment for ics, vol. 70, 2000, pp. 292-294. ical doctors to exchange digitized medical navigating 3D models of anatomic struc- 4. L. Makris et al.,“Teleworks:A CSCW Application images, enabling an early form of collabora- tures and detecting pathologic lesions, as in for Remote Medical Diagnosis Support and Tele- tion. Collaboration through PACSs, howev- actual endoscopy.Recently,surgical simula- consultation,” IEEE Trans. Information Technology in er, is limited to 2D images, such as x-rays, tion has been combined with augmented- Biomedicine, vol. 2, no. 2, June 1998, pp. 62-73. computed tomography (CT), and magnetic reality technology,enabling doctors to uti- 5. U. Engelmann et al.,“A Three-Generation Model resonance imaging (MRI). Furthermore, lize the simulation results in the operating for Teleradiology,” IEEE Trans. Information Technolo- PACSs do not allow for online collaboration. room.10 Moreover, medical personnel can gy in Biomedicine, vol. 2, no. 1, Mar.1998, pp. 20-25. CSCW technology enables a wide vari- acquire practical experience using, for 6. A.Abrardo and A.L. Casini,“Embedded Java in a ety of new applications, such as telepathol- example, laparoscopic11 and implant Web-Based Teleradiology System,” IEEE Internet ogy, teledermatology, teleradiology. Many surgery simulation.These systems are use- Computing, vol. 2, no. 3, May/June 1998, pp. 60-68. researchers, including Chronaki and col- ful for effectively treating patients; however, 7. R. Sacile et al.,“Collaborative Diagnosis over the leagues1 and Bai and colleagues,2 developed because they are generally developed as Internet: A Working Experience,” IEEE Internet Internet-based medical collaboration sys- standalone products, users must meet in Computing, vol. 3, no. 6, Nov./Dec. 1999, pp. 29-37. tems that include services like virtual person or communicate ofﬂine to discuss 8. K.H. Englmeier et al.,“Virtual Bronchoscopy Based workspaces, bulletin boards, and digital their surgery plans. on Spiral-CT Images,” Proc. SPIE Conf. Medical Imag- audio tools. Other research projects apply Because 3D medical systems are based ing, Soc. of Photo-Optical Instrumentation Engi- virtual reality and robot technology to sur- on 2D images, they can use the exchange neers, Bellingham,Wash., 1998, pp. 427-438. gical operations.3 Some systems, like Tele- functionality of PACS to enable collabora- 9. J. Beier et al., “Quantification and Virtual works4 and the Chili teleradiology system,5 tion using 3D models. Angioscopy of Aortic Stenoses by CT and MR,” allow remote users to exchange medical Proc. CAR 98 (Tokyo), Elsevier, Amsterdam, images and records and to work interac- References Netherlands, 1998, p. 876. tively.Abrardo and Casini6 and Sacile and 1. C.E. Chronaki et al.,“WebOnCOLL:Medical Col- 10. W.E.L.Grimson et al.,“An Automatic Registration colleagues7 use Web-based CSCW func- laboration in Regional Healthcare Networks,” IEEE Method for Frameless Stereotaxy, Image Guided tions on medical image data for teleradiol- Trans. Information Technology in Biomedicine, vol. 1, Surgery, and Enhanced Reality Visualization,” IEEE ogy and telepathology.Most of these med- no. 4, Dec. 1997, pp. 257-269. Trans. Medical Imaging, vol. 15, no. 2,Apr. 1996, pp. ical applications enhance their collaborative 2. J. Bai,Y.Zhang, and B. Dai,“Design and Develop- 129-140. functions with basic CSCW tools, such as ment of an Interactive Medical Teleconsultation 11. P.Oppenheimer et al.,“Laparoscopic Surgical Sim- video- and audioconferencing, directory System over the World Wide Web,” IEEE Trans. ulator and Port Placement Study,” Studies in Health services, whiteboards, and text-based chat. Information Technology in Biomedicine,vol.2,no.2, Technology and Informatics, vol. 70, 2000, pp. 233- Major applications of 3D simulation sys- June 1998, pp. 74-79. 235.

tion and reference. A demo of the system is avail- The system must be highly accurate to accom- able at http://www.cybermed.co.kr/cosurgeon/index. modate complex surgical procedures. html. This article describes Co-Surgeon’s design and Treatment can extend over a long period of implementation and reports results from laboratory time, and the system might have to generate tests run using a prototype system. many treatment plans for a single patient.

System Design Requirements Co-Surgeon’s distinguishing features are its use of Keeping these points in mind, we identify the 3D medical models and its capability for simulat- requirements for an effective collaborative surgery ing various surgical methods that can be shared simulation system. among multiple users. The system’s key technolo- gies are 3D surgical simulation and CSCW. Synchronous and asynchronous collaboration. Co-Surgeon differs from other CSCW applica- Collaboration in a networked environment can tions in several respects. be synchronous or asynchronous.2 In synchronous mode, users collaborate on the simulation It deals with medical models that range from while sharing a view in real time. Users who several to hundreds of megabytes. cannot attend a session should be able to

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Synchronous collaboration Asynchronous collaboration

Orthodontist

Radiologist Server

Surgeon Co-Surgeon Doctors

TCP/IP Identify patient Identify patient

DBMS

TCP/IP Download models Patient data Download models

Event history

Download Download event history event history DICOM

Cooperate PACS Simulate

Clients Clients

Figure 1. Co-Surgeon client-server architecture.The server and clients communicate with each other using TCP/IP. The server accesses a PACS using the DICOM standard.

review the session and contribute to the simu- munication systems (PACSs). These requirements lation after the session is over. are outside the scope of this article and thus are not Real-time collaboration with large-sized data. speciﬁcally addressed here. For an effective, natural online collaboration using large-sized data (often several tens of Client-Server Architecture megabytes’ worth), communication and data Co-Surgeon uses the Internet client-server archi- exchange methods should be able to overcome tecture illustrated in Figure 1. The server imple- network delay, so that the system can instant- ments a database management system (DBMS) that ly provide remote users with up-to-date stores and manages patient medical records, med- changes to the images and models. ical images and models, treatment procedures, and Effective control of multiple users’ right to surgical plans. The server also maintains the data speak. Unless the system has a mechanism for created during collaborative sessions. controlling which participant can speak at any We have designed a simple database schema one time, user operations can collide. The com- in the server-side DBMS. The data required for plexity and required accuracy of surgical oper- our collaborative surgical simulation includes ations makes consistency control an important simple x-ray, CT, and MRI images, and 3D mod- aspect of CSCW in surgical simulations. els. The images are obtained from conventional Management of surgical procedures. Treat- medical devices; the models, from a 3D medical ment plans consist of a number of detailed modeling system. The data can be readily pre- steps and can involve many alternative pared since most of the image acquisition and surgery plans. Thus there must be systematic modeling systems are interconnected with a management of surgical operations and oper- PACS. The server communicates with a PACS ational procedures. using the DICOM format, the international standard for interconnecting medical imaging Other requirements include patient information devices on standard networks. encoding, access authorization, use of open stan- To use Co-Surgeon’s collaborative functions at dards, such as Digital Imaging and Communica- the client side, an authorized user must obtain the tions in Medicine (DICOM) and Health Level 7 data to be used in the session. The session orga- (HL7), for transparent data exchange, and interop- nizer usually prepares the data and can upload it eration with existing picture archiving and com- to the server for a prescheduled meeting. Other par-

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view by registering and overlapping a 2D image Root: Surgery plan ID on a 3D model. With V-works’ surgical simulation module, a Node: Event user can create operation plans using marking, Sequence of treatment plan measurement, cutting, and movement functions. Sequence of the treatment plan currently selected In our system, the client program interacts with the Leaf: Clicking a leaf node selects server for event exchange, token control, and use a sequence of treatment plan of the event tree and multilayered collaboration tree (MCT), which are described in the following section. The required communication capability is implemented on top of V-works’ modeling and simulation functions. With the current version of Co-Surgeon, users can collaboratively use most of V-works’ 3D manipulation and surgical simulation functions. Implementation We implemented a Co-Surgeon prototype that meets the requirements we identiﬁed for a collabo- Plan 1 Plan 2 Plan 3 rative surgery simulation system. (See the “Using Co-Surgeon for Collaborative Treatment” sidebar Figure 2. Event tree. An event tree records the procedures used dur- on page 53 for a sample scenario.) ing a surgical simulation. Nodes represent events, and edges represent the relationships between events. Synchronous and Asynchronous Collaboration Users can participate in the simulation either syn- ticipants simply download the server-side data chronously or asynchronously. In synchronous before joining the session. For a spontaneous meet- mode, participants share a global view. When a ing, the data can be obtained from sources other user action changes the current view (for example, than the server such as users’ local computers and if a user rotates a model), the change should appear image storage servers. In this case, the participants on all other views. An exchange mechanism catch- use only the server’s collaboration functions. es any event that changes the model and passes it The client program provides 3D surgery simula- to the other participants. A token control mecha- tion and planning through global and private nism coordinates the multiple participants’ actions views. The global view contents are shared trans- in the global view. parently among all users, while private views are Users who do not participate in an online ses- concealed from other users. Since the server and sion can replay the simulation procedure performed the clients communicate via TCP/IP, anyone con- by the session participants. They can also propose nected to the Internet can use the system. new surgical procedures or modify existing ones. To support asynchronous collaboration, Co-Sur- 3D Surgical Simulation geon maintains an event tree. An event tree records Co-Surgeon uses V-works, a commercial software the history of events used to simulate a surgical application for 3D medical modeling and surgical process (see Figure 2). Nodes represent events, and simulation, as its client program. The basic func- edges represent the precedence relationship tions of V-works are as follows: between two adjacent events. The root node is an abstraction of the simulated surgery. Each path The system can reconstruct 3D models of from the root node to a leaf node represents an human organs from various data sources, such alternate surgical process. The event tree can also as CT and MRI. be used in synchronous mode. While working in a Users can manipulate the models using a vari- private view, a user can generate a local event tree, ety of interactive functions. For example, a user which can be used to modify the global event tree can browse a model using a mouse, navigate when it is the user’s turn to speak. inside the model, or examine a cross-sectional In an asynchronous collaboration session, a user

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Table 1.Types of event messages. first downloads a 3D model and its associated event tree. To observe the previous actions, the user Message Type Description chooses one of the nodes, and the system updates the view by applying all the events from the root Object selection Identifies selected object. to the chosen node in order. During the asynchro- Object translation Identifies the coordinates of translation. nous session, the user can modify a part of the Object rotation Identifies the axis and angle of rotation. event history file or suggest a new surgery plan, Marking Identifies the coordinates of a list of points forming a creating a new path where the change is intro- marking line. duced. Once the modified history file is saved in Measuring Specifies measurement type (angle and length) and the server, other participants can use it in other coordinates of datum lines. synchronous or asynchronous sessions. Cutting Segments the currently selected model along the marked Asynchronous collaboration mode is also use- line. ful when a patient’s treatment lasts for several Undo Returns the view to the previous state. months or years. In this case, doctors determine or Redo Goes to the next state. change the treatment and surgery plan while mon- itoring the results of earlier treatment. In our synchronous mode, only one participant Event Exchange controls the global view at any time. To make this To reduce network delay, Co-Surgeon uses an event possible, the system maintains a token during a exchange mechanism. At the beginning of a ses- collaborative session. The user possessing the token sion, participants download the same model, so can work in the global view; other participants can that they all have the same initial global view. only observe the global view or manipulate objects Users can select and manipulate objects in this in their local views. To obtain control, a participant view. Selected objects can be anything that appears must first request a token. The request is placed in on the view, such as 3D models, marking lines, and a queue, which is managed by the session supervi- folder elements. sor (usually the initiator of the collaborative ses- There are three basic types of object manipula- sion). While coordinating the session, the supervi- tion: selection, translation, and rotation. Surgical sor gives and collects the token according to the simulation requires more complicated actions, such token management policy. Because the token-con- as marking, measuring, and cutting. Other events trol mechanism restricts user freedom, improving are undo and redo. A control template can be used the system’s usability is an important further with a mouse to modify rotation angle and trans- research issue.3,4 lation distance or control the model manipulation minutely. Whenever any of these events occurs on Procedure Management the client side, the system detects it and transforms Many quantitative and qualitative factors influence it into a corresponding message type. The impor- decisions on treatment and surgery. Treatment and tant message types used in Co-Surgeon are surgery might depend on the patient’s pathology described in Table 1. or health condition, or on the surgeon’s treatment The system then broadcasts the message to all preference. For example, corrective facial surgery the other clients via the server. When a client can involve various combinations of surgical receives the message, the client applies it to the methods depending on the severity of the deformi- model in its global view so that it matches the view ty and local conditions such as missing and/or of the client that made the change. The small size impacted teeth and surrounding soft tissues. There- of the messages minimizes network delay. fore, plans need to be differentiated for each patient. Token Control We propose a multilayered collaboration tree for Consistency is important in Co-Surgeon because the managing surgical procedures in the collaborative system involves very accurate movement and nav- surgical simulation. An MCT is a hierarchical igation of complex structures. If several users were schema for classifying the procedures in a conven- to take concurrent action on the same object, the tional directory or folder structure. Figure 3 gives global view could be easily disordered. We adopt a an example MCT showing a part of the treatment, simple and well-known token-control mechanism planning, and simulation stages of orthodontic that maintains consistency by regulating multiple treatment and orthognathic surgery for a protrud- participants’ actions in the shared global view. ing chin. Each of the tree’s three layers consists of

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Protruding chin

Orthodontic Orthodontic treatment with treatment with both upper and lower jaw lower jaw surgery surgery Treatment scheme layer

Presurgical Postsurgical Presurgical S.S.R.O. Genioplasty Postsurgical orthodontic orthodontic orthodontic 9.5mm back 3mm cut orthodontic treatment treatment treatment treatment

Body S.S.R.O. Le Fort 1 Postsurgical Body 3.5mm advance osteotomy 13mm back osteotomy orthodontic 3mm post. Imp. treatment Planning layer

Click and Root Treatment scheme Select object Select menu drag "Draw "Maxilla" "Surgery Specific treatment Event Le Fort 1" osteotomy line" Selected plan

Select menu Select object Click and "Rotational "Tip of drag "Rotate axis" incisor" segment" Simulation layer

Figure 3. A multilayered collaboration tree.The MCT allows Co-Surgeon users to classify surgical procedures in a directory or folder structure.

a set of parallelogram nodes. The root node (the network latency, we set up LAN and Internet con- node above the first layer) represents a case of figurations as shown in Table 2 (on p. 54). anomaly. The first layer provides a set of treatment An event can be generated at either the server schemes that can be applied to the anomaly. Each or a client and is sent to all clients via the server. scheme is deployed into a parallelogram node in As soon as a client receives the event, it replies via the planning layer. The trees in this layer represent the server. We measured the round-trip time — that different plans and sequences for the treatment is, the duration from event generation to the last scheme. Circular nodes denote specific treatment reply — of 20 events, and report the average and methods. A circular node deploys again into the standard deviations in Table 2. These results show simulation layer. A parallelogram node in this layer that with our LAN and Internet settings, the net- contains an event tree. work latency is less than 1.0 second. An MCT also provides systematic classification Because the server broadcasts an event to all of surgical methods, allowing users to easily iden- clients, an increase in the number of clients has lit- tify the surgical procedure that best fits their case, tle influence on network latency. Considering that and can be used as a repository of treatment and the Internet bandwidth during our test was on planning experiences. average 287.0 Kbps, our results are quite tolerable for the collaborative surgical simulation. This laten- Experimental Results cy depends, however, on the amount of network We ran a set of experiments to test the system’s traffic. The larger standard deviation for the Inter- network latency and rendering performance. To test net environment indirectly indicates this.

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Using Co-Surgeon for Collaborative Treatment

In our scenario, a patient with a protruding Local 2D views Global 3D view V-works™ menu chin needs both orthodontic treatment and orthognathic surgery. Dr. Lee, an orthodontist, examines the patient and obtains the patient’s treatment history, facial measurements, oral and facial pho- tographs, and so on.

Establishing a Session After several months of preorthodontic treatment, a CT scan is taken. Dr. Lee reconstructs 3D models of the skull and face from the CT data using V-works, and uploads the models and all medical records to the Co-Surgeon server.Dr.Lee schedules an online collaborative session with Dr. Choi, an oral and maxillofacial surgeon, and User list/ Local 3D view Chatting window MCT tree Dr. Kim, a plastic surgeon, both of whom token menu are located at different sites.At the sched- Figure A. The Co-Surgeon user interface. The large view pane in the upper center is the global uled time, Dr.Lee creates a session by reg- view pane. This view is updated for all users when the user with control makes a change to istering it in the Co-Surgeon server.The the model. other participants log into the session by submitting the server address, their user id, and their password.This establishes a com- When Dr. Lee completes his munication channel among all the partici- simulation, Dr. Choi requests and pants via the Co-Surgeon server. receives control. He points out that All participants initialize their global the patient has upper-jaw under- view by downloading the patient models. growth, and recommends a com- Dr.Lee proposes his treatment plan to cor- plementary operation to improve rect the protruding chin while manipulat- the aesthetic profile. Dr.Choi simu- ing the 3D model and simulating his plan on lates this new method in the global the Co-Surgeon user interface. view. After Dr. Choi’s simulation operation, the participants rotate Manipulating the View and zoom in and out on the model Figure A is a snapshot of the Co-Surgeon to evaluate the final plan. interface.The large view pane at the upper center is the global view.All participants Collaborating During and can observe Dr. Lee’s operations in this After the Session global view. Dr.Lee can rotate or translate The multilayered collaboration tree the model using a mouse. He can also use (MCT) in Figure B (which is an Figure B. Multilayered collaboration tree. The MCT the mouse to cut and join the model. Dur- enlarged version of the one in Figure shows all the surgical procedures that have been ing the manipulation, the direction and dis- A) shows all the surgical operations simulated in the session. tance of the movement is displayed on the simulated in the session. During col- screen.The view panes at the left-hand side laboration, participants can exchange and another 3D view pane in the lower left their opinions using typical CSCW func- laboration mode. The user can suggest are all private views.The user is currently tions, such as the chatting window at the alternate plans by branching the MCT in the examining the patient model with 2D bottom of the screen or Microsoft’s Net- server. Any modification in the tree may be images of axial, coronal, and sagittal views, Meeting’s video- and audioconferencing communicated to the other participants and the 3D model from a different view tools. using e-mail, and then they can review it angle. Since the local user owns this view, Anyone who is absent from the syn- synchronously or asynchronously.Doctors no other participants can see any opera- chronous collaboration session can review can also use asynchronous mode to explain tion performed in it. the final plan using the asynchronous col- the treatment plan to patients.

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Table 2.Network latency for events traveling between local and remote computers over LAN and Internet connections.

LAN conﬁgurations Internet conﬁgurations

Location of LC (1) LC (2) LC (3) LC (4) LC (1) to LC (1) to LC (2) to event generation RC (1) RC (2) RC (2) Server Average (msec)150.8 157.9 187.4 192.2 522.2 527.2 509.0 SD 27.8 30.9 13.4 12.5 284.1 128.7 139.7 Local clientAverage 173.3 292.5 344.4 341.6 585.9 623.0 762.4 SD 25.5 45.0 43.7 31.7 60.2 127.9 300.6 Remote clientAverage - - - - 766.4 946.0 971.0 SD - - - - 466.7 209.9 186.3 Note: The average bandwidth for LAN connections was 56.0 Mbps; the link speed was 100 Mbps. For Internet connections, the average bandwidth was 287.0 Kbps. The integer in the parenthesis is the number of computers.

Table 3.Rendering time for a 3D model time motion of changes to the model. In the cur- (on a Pentium III PC with GeForce2 MX, rent system, an event catches only the final change, an OpenGL accelerating video card). so users see only the final rendering. We could approximate real-time motion by interpolating the initial and final model. This, however, increases the Model size (Kbps) Rendering time (msec) computation time required to render the model. 1,207 29.9 Other research issues include constructing a 2,099 44.4 library of surgical methods and facilitating world- 3,890 73.2 wide information sharing. Standards, such as 5,236 103.4 DICOM for the exchange of medical images and 7,989 150.6 HL7 for the exchange and sharing of patient infor- 10,608 194.2 mation, are key to the ubiquity of such interoper- 21,216 380.2 ating systems. Consideration should also be given 31,824 574.7 to the security of patient information — this includes legal as well as technological issues. Also important for practical acceptance of the system When a client receives an event, the client com- are Internet quality-of-service issues and cost/ben- puter has to process it. The most complex task in efit analyses of this type of Internet-based collabo- terms of computation time is rendering a 3D model. ration in medicine and medical training. We have prepared eight models, ranging from 1.2 Mbytes to 31.8 Mbytes. As Table 3 shows, the Acknowledgments required rendering time is proportional to the This study was partly supported by Korea Health 21 R&D Pro- model size. Considering the data from Tables 2 and ject grant No. HMP-99-E-10-0003, Ministry of Health and Wel- 3, we can conclude that all participants in the fare, Republic of Korea. The research was carried out at the experimental environment can share the global Research Institute of Engineering Science at Seoul National Uni- view within about 1.0 second. versity. We would like to thank Won-Sik Yang at SNU Hospital and anonymous referees for their constructive comments that Future Work have greatly improved the quality of the article. Special thanks Co-Surgeon uses a simple token control mecha- go to Byeong-Hyeon Ha and Jae Bum Lee for their time and nism, which ensures consistency while users efforts in the system implementation. manipulate the model. It is, however, restrictive, and users might find this unacceptable. To enhance References the system’s usability, we can adopt Sun and col- 1. J. Xia et al., “Three-Dimensional Virtual Reality Surgical leagues’ consistency model for real-time coopera- Planning and Simulation Workbench for Orthognathic tive editing systems.4 Their model allows multiple Surgery,” Int’l J. Adult Orthodontics and Orthognathic users to manipulate the global model concurrent- Surgery, vol. 15, no. 4, Winter 2000, pp. 265-282. ly while maintaining the required consistency. 2. S.F. Li, Q. Stafford-Fraser, and A. Hopper, “Integrating Syn- Another interesting issue is improving the real- chronous and Asynchronous Collaboration with Virtual

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Network Computing,” IEEE Internet Computing, vol. 4, no. Nam Kuk Kim is CEO of CyberMed, which provides 3D medical 3, May/June 2000, pp. 26-33. imaging software products and medical replica services. He 3. Y. Yang et al., “Real-time Cooperative Editing on the Inter- received BS and MS degrees from SNU, where he is cur- net,” IEEE Internet Computing, vol. 4, no. 3, May/June rently a doctoral candidate in the Industrial Engineering 2000, pp. 18-25. Department. His major research interests include 3D med- 4. C. Sun et al., “Achieving Convergence, Causality Preserva- ical visualization, image-guided surgery, rapid prototyping, tion, and Intention Preservation in Real-time Cooperative volume visualization, very large data visualization, CSCW, Editing Systems,” ACM Trans. Computer-Human Interac- and Internet applications. tion, vol. 5, no. 1, Mar. 1998, pp. 63-108. Jin Sup Yeom is an assistant professor in the Department of Yeongho Kim is an assistant professor in the Industrial Engi- Orthopedic Surgery at Eulji Medical University. He received neering Department at Seoul National University (SNU), MS, PhD, and MD degrees from SNU. He is interested in the Korea. His research interests include Internet and CSCW areas of spine surgery and computer-assisted orthopedic applications in engineering and medicine, Web-based work- surgery. His research topics include surgical treatment of ﬂow management systems, and product data management. spine disorders, surgical simulation, biomaterials, and ﬁnite He received BS and MS degrees from SNU, and a PhD from element methods. North Carolina State University at Raleigh. He is a member of the editorial board of the International Journal of Indus- Yong Oock Kim is an assistant professor in the Plastic Surgery trial Engineering — Applications and Practice, the Interna- Department at the College of Medicine of Yonsei Universi- tional Journal of Management Systems, and the Interna- ty, Korea, where he received MD and PhD degrees. He is tional Journal of CAD/CAM. interested in clinical applications of computer simulation surgery, electronic medical recording, Internet applications, Jeong-Ho Choi is a clinical fellow in the Department of Ortho- and telemedicine. He is a member of the International Con- dontics at SNU Hospital, Korea. He has MS and DDS degrees federation for Plastic, Reconstructive, and Aesthetic from SNU, where he is currently a doctoral student. His Surgery; American Society of Plastic Surgery; and the research interests include surgical orthodontics, dentofacial Korean Society of Plastic and Reconstructive Surgery. orthopedics, biomechanics, and computer applications. He has been a fellow of the World Federation of Orthodontists, Myeng Ki Kim is an associate professor in the Dental College and a member of the Information and Communication at SNU. He received a BS degree from SNU in 1977, and MS Committee of Korean Association of Orthodontists. and PhD degrees from the University of Michigan in 1986 and 1988, respectively. Kim’s research interests include Jongki Lee is a PhD candidate at SNU. He received BS and MS medical concept representation, medical imaging, and clin- degrees from SNU’s Dental College in 1997 and 1999, ical information systems. respectively. His research interests include medical imaging and medical knowledge representation. Readers can contact Yeongho Kim at [email protected].

EDITORIAL CALENDAR

JANUARY/FEBRUARY JULY/AUGUST Usability Engineering in Fault Tolerance Software Development SEPTEMBER/OCTOBER MARCH/APRIL Software Organizational Global Software Development Benchmarking

MAY/JUNE NOVEMBER/DECEMBER Organizational Change Ubiquitous Computing

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