• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.5
• /
• pp.25-38
• /
• 2013

Future wireless systems will be required to support the increasingly nomadic lifestyle of people. This support will be provided through the use of multiple overlaid networks which have very different characteristics. Moreover, these networks will be required to support the seamless delivery of today's popular desktop services, such as web browsing, interactive multimedia and video conferencing to the mobile devices. Thus one of the major challenges in the design of these mobile systems will be the provision of the quality of service (QoS) guarantees that the applications demand under this diverse networking infrastructure. We believe that it is necessary to use resource reservation and adaptation techniques to deliver these QoS guarantee to applications. However, reservation and pre-configuration in the entire service region is overly aggressive, and results in schemes that are extremely inefficient and unreliable. To overcome this, the mobility pattern of a user can be exploited. If the movement of a user is known, the reservation and configuration procedure can be limited to the regions of the network a user is likely to visit. Our proposed Proxy-UMP is not sensitive to increase of the search cost than other schemes and shows that the increasing rate of total cost is low as the SMR increases.

• Journal of KIISE:Information Networking
• /
• v.29 no.1
• /
• pp.86-96
• /
• 2002

In video conferencing system using H.263 encoding and decoding time is as important as compression rate is. To reduce encoding time, a number of methods were proposed. We use a method of them that reduces the computational complexity in motion estimation. The complexity is determined by three factors, such as a cost function, a search range parameter, and a motion search algorithm. In fact, it takes a lot of time to encode the video data on account of the cost function factor. That's the reason that we use the factor to reduce encoding time. In this paper, we tried to reduce total encoding time by reducing the number of calling the cost function. In case of a little moving, our algorithm enabled faster motion searching than TSS(Three Step Search) and NTSS(New TSS). Here, we called the algorithm by an ITSS(Improved TSS) that improves a shortcoming of NTSS requiring more checkpoints than TSS. For an experimentation, our algorithm was compared to other algorithms using PSNR, file size and SAD call times.

• The KIPS Transactions:PartC
• /
• v.13C no.4 s.107
• /
• pp.471-480
• /
• 2006

Recently, multimedia communication services, such as video conferencing and voice over IP, have been rapidly spread. H.323 is an international standard that specifies the components, protocols and procedures that provide multimedia communication services of real-time audio, video, and data communications over packet networks, including IP based networks. H.323 is applied to many commercial services because it supports various network environments and has a good performance. But communication services based on H.323 may have some problem because of current network trouble or mis-implementation of H.323. The understanding of this problem is a critical issue because it improves the quality of service and is easy to service maintenance. In this paper, we implement the analysis system for H.323 protocol wihch includes H.245, H.225.0, RTP, RTCP, and so on. Tills system is able to capture, parse, and present the H.323 protocol in real-time. Through the operation test and performance evaluation, we prove that our system is a useful to analyze and understand the problems for communication services based on H.323.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.8
• /
• pp.1960-1971
• /
• 1998

The researches and developments to provide multimedia communication services such as Video on Demand(VoDJ), real time video phonc and multipoint vidco conferencing on broadband ISDN environmcnts have been proceeded with activity. Specifications for Vol) services which is worked by Digital Audio-Visual Council(DAVIC) to support detail technologies including total service system that is consist of VoD server. delive[\! networl, and Set-Top Box(STB) had been already finished and ITU-T SG16 also recommended the standards of H.300 series terminal aspects for conversational multimedia services, But the architectures of multimedia tenninals recommended and specified by these organizations do not have an efficient st11lcture to provide all of retrieval, distrihution and conversational service due to a different point of view about multimedia terminals and services. In this paper, we analyzed the recornmendatio!E and the specifications of intemational public and private organizations like lTU-T, DAVIC and ATM forum. As a result of these analysis. we propose an efficient terminal architecture, and then we have designed, lmplemented the multimedia communication terminal for offering VoI) and real- time conversation ,,, functional module test according to the individual commumication service session and confirined the validiry or terminal implemented to be used on broadband ISDK environments.

• Journal of Korea Multimedia Society
• /
• v.14 no.5
• /
• pp.658-668
• /
• 2011

Over the past decade, the improvement of communications technologies and the rapid spread of www (World Wide Web) have brought on the exponential growth of users using Internet and real time multimedia multicast services like video conferencing, tele-immersive virtual reality, and Internet games. The dense-wavelength division multiplexing (DWDM) networks have been widely accepted as a promising approach to meet the ever-increasing bandwidth demands of Internet users, especially in next generation Internet backbone networks for nation-wide or global coverage. A major challenge in the next generation Internet backbone networks based on DWDM technologies is the resolution of the multicasting RWA (Routing and Wavelength Assignment) problem; given a set of wavelengths in the DWDM network, we set up light-paths by routing and assigning a wavelength for each connection so that the multicast connections are set-upped as many as possible. Finding such optimal multicast connections has been proven to be Non-deterministic Polynomial-time-complete. In this paper, we suggest a new heuristic multicast routing and wavelength assignment method for multicast sessions called DVS-PMIPMR (Differentiated Virtual Source-based Priority Minimum Interference Path Multicast Routing algorithm). We measured the performance of the proposed algorithm in terms of number of wavelength and wavelength channel. The simulation results demonstrate that DVS-PMIPMR algorithm is superior to previous multicast routing algorithms.

• Journal of Internet of Things and Convergence
• /
• v.6 no.4
• /
• pp.27-32
• /
• 2020

Along with the aging of the population, the number of dementia patients is increasing, and the social and economic burden is also increasing. Currently, the effective way to manage dementia patients is to identify patients with dementia early. However, in rural and island areas where medical staff are scarce, there is a problem that it is difficult to visit a hospital and get an early examination. Therefore, we propose a remote early detection system for dementia to solve the problems. The remote dementia early diagnosis system is a system that allows a patient to receive examination and treatment from a remote dementia expert using remote medical technology based on real-time image communication. The remote early diagnosis system for dementia consists of a local client system used by medical staff at health centers in the island, an image server that transmits, stores and manages images, and an expert client used by remote dementia experts. The local client subsystem satisfies the current medical law's remote collaboration by allowing the patient to use it with the health center's medical staff. In addition, expert clients are used by dementia experts, and can store/manage patient information, analyze patient history information, and predict the degree of dementia progression in the future.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.1
• /
• pp.300-308
• /
• 2021

The epidemic of COVID19 caused a big change in design collaboration, which has been conducting using face-to-face interaction. Designers actively used video conferencing and online document tools in situations where face-to-face meetings were difficult, and this gave them an opportunity to experience that non-face-to-face collaboration can be more effective in a specific design process. In this regard, this study attempted to find out which activities during the design process are more compelling in face-to-face collaboration or non-face-to-face collaboration. To do this, three user experience design projects conducted after the COVID19 epidemic were analyzed through a retrospective interview method. As a result, during four design stages, 'Discover, Define, Develop, Deliver', face-to-face collaboration is necessary for the areas that require creative problem solving through active interaction. In contrast, non-face-to-face collaboration is preferred and more effective when designers need their own space and proceed their design work. In addition, the aspects of design tools supporting non-face-to-face collaboration were also illustrated. Findings discovered through this study are expected to contribute to research on the design process later.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.1
• /
• pp.483-497
• /
• 2022

Recently, due to COVID-19, non-face-to-face online lectures are being held all over the world. In higher education in the post-corona era, distance learning has become the main teaching and learning method. At this time, Metaverse is being proposed as a new alternative. Metaverse has basic elements such as avatars, 3D space, and activities accompanied by interaction, which can be seen as a difference compared to existing VR (Virtual Reality) contents. This study designed and built an educational metaverse platform that can be applied to actual lectures by reflecting the three elements of the metaverse.In addition, we implemented a cross-device-platform that supports various devices such as HMDs, smartphones, tablets, and PCs by reflecting user requirements through usability tests such as middle school, high school, college students, and parents, so that anyone can easily participate in Metaverse lectures. Currently, the metaverse platform is being developed and serviced in various ways, but there are hardly any services designed for education. Just as services such as Zoom, the existing video conferencing solution, were used for non-face-to-face education, some functions of the currently serviced metaverse are utilized for education and used in the form of a one-time event. The educational metaverse platform developed through this study is expected to be a reference in constructing the metaverse for education in the future.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.3
• /
• pp.427-438
• /
• 2022

With the recent growing importance over safety management the need for advanced and technical approaches for on-site safety inspection methods has increased. Railway construction is subject to its own particular set of temporal and spatial challenges due to its unique facilities and equipment. This study aimed to investigate the field characteristics of railway infrastructure and improve the conventional field safety management methods by identifying the most appropriate features of AR technology. Group interviews and surveys were conducted with field safety experts to derive the major problems and inspection needs. Subsequently, various features of AR, such as BIM model projection, and remote conferencing, were investigated to determine their applicability to address safety issues. As a result, four problems in the current safety management process, such as 'lack of time due to the conventional inspection method and inspection of areas that are difficult to access', and three major inspection types, such as 'observance of work procedures, status of installation, adequate dimensional spacing', were identified to be improved when adopting AR based techniques. Furthermore, AR technology utilizing plans to solve safety inspection problems and effectively manage major inspection types were proposed, and a follow up survey was conducted with the same field safety experts to derive the priority of technology development.

• Journal of the Institute of Convergence Signal Processing
• /
• v.23 no.3
• /
• pp.115-122
• /
• 2022

With the outbreak of COVID-19 a few years ago, video conferencing and electronic document work have increased, and for this reason, the proportion of computer work among modern people's daily routines is increasing. However, as more and more people work on computers in the wrong posture for a long time, the number of patients with poor eyesight and text neck is increasing. Until recently, many studies have been published to correct posture, but most of them have limitations that users may experience discomfort because they have to correct posture by wearing equipment. A posture correction sensor algorithm is proposed to prevent access to the minimum distance between a computer monitor and a person using an ultrasonic sensor device. At this time, an algorithm for minimizing false alarms among warning alarms that sound at the minimum distance is also proposed. Because the ultrasonic sensor device is used, posture correction can be performed without attaching a device to the body, and the user can relieve discomfort. In addition, experimental results showed that accuracy can be improved by reducing false alarms by removing more than half of the noise generated during distance measurement.