• Title/Summary/Keyword: Multi-users

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A Study of Performance Analysis on Effective Multiple Buffering and Packetizing Method of Multimedia Data for User-Demand Oriented RTSP Based Transmissions Between the PoC Box and a Terminal (PoC Box 단말의 RTSP 운용을 위한 사용자 요구 중심의 효율적인 다중 수신 버퍼링 기법 및 패킷화 방법에 대한 성능 분석에 관한 연구)

  • Bang, Ji-Woong;Kim, Dae-Won
    • Journal of Korea Multimedia Society
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    • v.14 no.1
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    • pp.54-75
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    • 2011
  • PoC(Push-to-talk Over Cellular) is an integrated technology of group voice calls, video calls and internet based multimedia services. If a PoC user can not participate in the PoC session for various reasons such as an emergency situation, lack of battery capacity, then the user can use the PoC Box which has a similar functionality to the MM Box in the MMS(Multimedia Messaging Service). The RTSP(Real-Time Streaming Protocol) method is recommended to be used when there is a transmission session between the PoC box and a terminal. Since the existing VOD service uses a wired network, the packet size of RTSP-based VOD service is huge, however, the PoC service has wireless communication environments which have general characteristics to be used in RTSP method. Packet loss in a wired communication environments is relatively less than that in wireless communication environment, therefore, a buffering latency occurs in PoC service due to a play-out delay which means an asynchronous play of audio & video contents. Those problems make a user to be difficult to find the information they want when the media contents are played-out. In this paper, the following techniques and methods were proposed and their performance and superiority were verified through testing: cross-over dual reception buffering technique, advance partition multi-reception buffering technique, and on-demand multi-reception buffering technique, which are designed for effective picking up of information in media content being transmitted in short amount of time using RTSP when a user searches for media, as well as for reduction in playback delay; and same-priority packetization transmission method and priority-based packetization transmission method, which are media data packetization methods for transmission. From the simulation of functional evaluation, we could find that the proposed multiple receiving buffering and packetizing methods are superior, with respect to the media retrieval inclination, to the existing single receiving buffering method by 6-9 points from the viewpoint of effectiveness and excellence. Among them, especially, on-demand multiple receiving buffering technology with same-priority packetization transmission method is able to manage the media search inclination promptly to the requests of users by showing superiority of 3-24 points above compared to other combination methods. In addition, users could find the information they want much quickly since large amount of informations are received in a focused media retrieval period within a short time.

A Study on Development and Prospects of Archival Finding Aids (기록 검색도구의 발전과 전망)

  • Seol, Moon-Won
    • The Korean Journal of Archival Studies
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    • no.23
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    • pp.3-43
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    • 2010
  • Finding aids are tools which facilitate to locate and understand archives and records. Traditionally there are two types of archival finding aids: vertical and horizontal. Vertical finding aids such as inventories have multi-level descriptions based on provenance, while horizontal ones such as catalogs and index are tools to guide to the vertical finding aids based on the subject. In the web environment, traditional finding aids are evolving into more dynamic forms. Respecting the principles of provenance and original order, vertical finding aids are changing to multi-entity structures with development of ISAD(G), ISAAR(CPF) and ISDF as standards for describing each entity. However, vertical finding aids can be too difficult, complicated, and boring for many users, who are accustomed to the easy and exciting searching tools in the internet world. Complementing them, new types of finding aids are appearing to provide easy, interesting, and extensive access channels. This study investigates the development and limitation of vertical finding aids, and the recent trend of evolving new finding aids complementing the vertical ones. The study finds three new trends of finding aid development. They are (i) mixture, (ii) integration, and (iii) openness. In recent days, certain finding aids are mixed with stories and others provide integrated searches for the collections of various heritage institutions. There are cases for experimenting user participation in the development of finding aids using Web 2.0 applications. These new types of finding aids can also cause some problems such as decontextualised description and prejudices, especially in the case of mixed finding aids and quality control of user contributed annotations and comments. To solve these problems, the present paper suggests to strengthen the infrastructure of vertical finding aids and to connect them with various new ones and to facilitate interactions with users of finding aids. It is hoped that the present paper will provide impetus for archives including the National Archives of Korea to set up and evaluate the development strategies for archival finding aids.

Methodologies for Enhancing Immersiveness in AR-based Product Design (증강현실 기반 제품 디자인의 몰입감 향상 기법)

  • Ha, Tae-Jin;Kim, Yeong-Mi;Ryu, Je-Ha;Woo, Woon-Tack
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.44 no.2 s.314
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    • pp.37-46
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    • 2007
  • In this paper, we propose technologies for enhancing the immersive realization of virtual objects in AR-based product design. Generally, multimodal senses such as visual/auditory/tactile feedback are well known as a method for enhancing the immersion in case of interaction with virtual objects. By adapting tangible objects we can provide touch sensation to users. A 3D model of the same scale overlays the whole area of the tangible object so the marker area is invisible. This contributes to enhancing immersion. Also, the hand occlusion problem when the virtual objects overlay the user's hands is partially solved, providing more immersive and natural images to users. Finally, multimodal feedback also creates better immersion. In our work, both vibrotactile feedback through page motors, pneumatic tactile feedback, and sound feedback are considered. In our scenario, a game-phone model is selected, by way of proposed augmented vibrotactile feedback, hands occlusion-reduced visual effects and sound feedback are provided to users. These proposed methodologies will contribute to a better immersive realization of the conventional AR system.

A Study of Quality Improvement Methods of Archival Contents Service - With as the Central Figure of Cases among Korea and England and Japan - (기록정보콘텐츠의 품질향상 방안 연구 - 한국·영국·일본의 사례비교를 중심으로 -)

  • Yang, In-Ho
    • The Korean Journal of Archival Studies
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    • no.23
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    • pp.87-139
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    • 2010
  • Unlike in the past, a new paradigm has been presented which the use of records is much more important than the preservation of those in the present. It will be necessary for users to signalizes the value of records and to make themselves easily accessible to records in order that records should be more effectively used. To meet the needs of the times, it is the very 'Contents' that starts to attract public attention. National Archives in England produces and provides contents utilizing multi-media by using digital technology on various sorts of archives which England has. In addition to England, Asian Historical Records center in Japan in Japan makes Archival Contents Service reflecting users' needs and continues to update the latest contents. What is more, National Archives of Korea has recently promoted the introduction of digital archive by the change of archival paradigm in records management, and it is giving an impetus to the development of contents in the digital archive. In fact, it is crucial to keep as many contents as possible and to give service to public, but it will not be possible to get positive response from public and to offer much higher level of archival information service until the quality of contents is highly improved. Accordingly, this manuscript analyzed the feature and type of contents which National Archives of Korea provides with cases of both TNA in England and Asian Historical Records center in Japan, each of which has different characteristics. Also, it dealt with several methods of the usage of contents in those organizations. Furthermore, this study explained what kind of contents and feedback are given to users. Moreover, it divided the components of contents of three institutions as mentioned into three by information provided and evaluated the quality of contents by establishing the details of contents. In addition, there were implications for archives with regard to reference for building contents.

H.264/SVC Spatial Scalability Coding based Terrestrial Multi-channel Hybrid HD Broadcasting Service Framework and Performance Analysis on H.264/SVC (H.264/SVC 공간 계위 부호화 기반 지상파 다채널 하이브리드 고화질 방송 서비스 프레임워크 및 H.264/SVC 부호화 성능 평가)

  • Kim, Dae-Eun;Lee, Bum-Shik;Kim, Mun-Churl;Kim, Byung-Sun;Hahm, Sang-Jin;Lee, Keun-Sik
    • Journal of Broadcast Engineering
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    • v.17 no.4
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    • pp.640-658
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    • 2012
  • One of the existing terrestrial multi-channel DTV service frameworks, called KoreaView, provides four programs, composed of MPEG-2 based one HD video and H.264/AVC based three SD videos within one single 6MHz frequency bandwidth. However the additional 3 SD videos can not provide enough quality due to its reduced spatial resolution and low target bitrates. In this paper, we propose a framework, which is called a terrestrial multi-channel high quality hybrid DTV service, to overcome such a weakness of KoreaView services. In the proposed framework, the three additional SD videos are encoded based on an H.264/SVC Spatial Base layer, which is compliant with H.264/AVC, and are delivered via broadcasting networks. On the other hand, and the corresponding three additional HD videos are encoded based on an H.264/SVC Spatial Enhancement layer, which are transmitted over broadband networks such as Internet, thus allowing the three additional videos for users with better quality of experience. In order to verify the effectiveness of the proposed framework, various experimental results are provided for real video contents being used for DTV services. First, the experimental results show that, when the SD sequences are encoded by the H.264/SVC Spatial Base layer at a target bitrate of 1.5Mbps, the resulting PSNR values are ranged from 34.5dB to 42.9dB, which is a sufficient level of service quality. Also it is noted that 690kbps-8,200kbps are needed for the HD test sequences when they are encoded in the H.264/SVC Spatial Enhancement layer at similar PSNR values for the same HD sequences encoded by MPEG-2 at a target bitrate of 12 Mbps.

A Study on the Performance Evaluation of G2B Procurement Process Innovation by Using MAS: Korea G2B KONEPS Case (멀티에이전트시스템(MAS)을 이용한 G2B 조달 프로세스 혁신의 효과평가에 관한 연구 : 나라장터 G2B사례)

  • Seo, Won-Jun;Lee, Dae-Cheor;Lim, Gyoo-Gun
    • Journal of Intelligence and Information Systems
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    • v.18 no.2
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    • pp.157-175
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    • 2012
  • It is difficult to evaluate the performance of process innovation of e-procurement which has large scale and complex processes. The existing evaluation methods for measuring the effects of process innovation have been mainly done with statistically quantitative methods by analyzing operational data or with qualitative methods by conducting surveys and interviews. However, these methods have some limitations to evaluate the effects because the performance evaluation of e-procurement process innovation should consider the interactions among participants who are active either directly or indirectly through the processes. This study considers the e-procurement process as a complex system and develops a simulation model based on MAS(Multi-Agent System) to evaluate the effects of e-procurement process innovation. Multi-agent based simulation allows observing interaction patterns of objects in virtual world through relationship among objects and their behavioral mechanism. Agent-based simulation is suitable especially for complex business problems. In this study, we used Netlogo Version 4.1.3 as a MAS simulation tool which was developed in Northwestern University. To do this, we developed a interaction model of agents in MAS environment. We defined process agents and task agents, and assigned their behavioral characteristics. The developed simulation model was applied to G2B system (KONEPS: Korea ON-line E-Procurement System) of Public Procurement Service (PPS) in Korea and used to evaluate the innovation effects of the G2B system. KONEPS is a successfully established e-procurement system started in the year 2002. KONEPS is a representative e-Procurement system which integrates characteristics of e-commerce into government for business procurement activities. KONEPS deserves the international recognition considering the annual transaction volume of 56 billion dollars, daily exchanges of electronic documents, users consisted of 121,000 suppliers and 37,000 public organizations, and the 4.5 billion dollars of cost saving. For the simulation, we analyzed the e-procurement of process of KONEPS into eight sub processes such as 'process 1: search products and acquisition of proposal', 'process 2 : review the methods of contracts and item features', 'process 3 : a notice of bid', 'process 4 : registration and confirmation of qualification', 'process 5 : bidding', 'process 6 : a screening test', 'process 7 : contracts', and 'process 8 : invoice and payment'. For the parameter settings of the agents behavior, we collected some data from the transactional database of PPS and some information by conducting a survey. The used data for the simulation are 'participants (government organizations, local government organizations and public institutions)', 'the number of bidding per year', 'the number of total contracts', 'the number of shopping mall transactions', 'the rate of contracts between bidding and shopping mall', 'the successful bidding ratio', and the estimated time for each process. The comparison was done for the difference of time consumption between 'before the innovation (As-was)' and 'after the innovation (As-is).' The results showed that there were productivity improvements in every eight sub processes. The decrease ratio of 'average number of task processing' was 92.7% and the decrease ratio of 'average time of task processing' was 95.4% in entire processes when we use G2B system comparing to the conventional method. Also, this study found that the process innovation effect will be enhanced if the task process related to the 'contract' can be improved. This study shows the usability and possibility of using MAS in process innovation evaluation and its modeling.

The Gradient Variation of Thermal Environments on the Park Woodland Edge in Summer - A Study of Hadongsongrim and Hamyangsangrim - (여름철 공원 수림지 가장자리의 온열환경 기울기 변화 - 하동송림과 함양상림을 대상으로 -)

  • Ryu, Nam-Hyong;Lee, Chun-Seok
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.6
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    • pp.73-85
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    • 2015
  • This study investigated the extent and magnitude of the woodland edge effects on users' thermal environments according to distance from woodland border. A series of experiments to measure air temperature, relative humidity, wind velocity, MRT and UTCI were conducted over six days between July 31 and August 5, 2015, which corresponded with extremely hot weather, at the south-facing edge of Hadongsongrim(pure Pinus densiflora stands, tree age: $100{\pm}33yr$, tree height: $12.8{\pm}2.7m$, canopy closure: 75%, N $35^{\circ}03^{\prime}34.7^{{\prime}{\prime}}$, E $127^{\circ}44^{\prime}43.3^{{\prime}{\prime}}$, elevation 7~10m) and east-facing edge of Hamyangsangrim (Quercus serrata-Carpinus tschonoskii community, tree age: 102~125yr/58~123yr, tree height: tree layer $18.6{\pm}2.3m/subtree$ layer $5.9{\pm}3.2m/shrub$ layer $0.5{\pm}0.5m$, herbaceous layer coverage ratio 60%, canopy closure: 96%, N $35^{\circ}31^{\prime}28.1^{{\prime}{\prime}}$, E $127^{\circ}43^{\prime}09.8^{{\prime}{\prime}}$, elevation 170~180m) in rural villages of Hadong and Hamyang, Korea. The minus result value of depth means woodland's outside. The depth of edge influence(DEI) on the maximum air temperature, minimum relative humidity and wind speed at maximum air temperature time during the daytime(10:00~17:00) were detected to be $12.7{\pm}4.9$, $15.8{\pm}9.8$ and $23.8{\pm}26.2m$, respectively, in the mature evergreen conifer woodland of Hadongsongrim. These were detected to be $3.7{\pm}2.2$, $4.9{\pm}4.4$ and $2.6{\pm}7.8m$, respectively, in the deciduous broadleaf woodland of Hamyansangrim. The DEI on the maximum 10 minutes average MRT, UTCI from the three-dimensional environment absorbed by the human-biometeorological reference person during the daytime(10:00~17:00) were detected to be $7.1{\pm}1.7$ and $4.3{\pm}4.6m$, respectively, in the relatively sparse woodland of Hadongsongrim. These were detected to be $5.8{\pm}4.9$ and $3.5{\pm}4.1m$, respectively, in the dense and closed woodland of Hadongsongrim. Edge effects on the thermal environments of air temperature, relative humidity, wind speed, MRT and UTCI in the sparse woodland of Hadongsongrim were less pronounced than those recorded in densed and closed woodland of Hamyansangrim. The gradient variation was less steep for maximum 10 minutes average UTCI with at least $4.3{\pm}4.6m$(Hadongsongrim) and $3.5{\pm}4.1m$(Hamyansangrim) being required to stabilize the UTCI at mature woodlands. Therefore it is suggested that the woodlands buffer widths based on the UTCI values should be 3.5~7.6 m(Hamyansangrim) and 4.3~8.9(Hadongsongrim) m on each side of mature woodlands for users' thermal comfort environments. The woodland edge structure should be multi-layered canopies and closed edge for the buffer effect of woodland edge on woodland users' thermal comfort.

Performance Evaluation of Wireless Sensor Networks in the Subway Station of Workroom (지하철 역사내 기능실에 대한 무선 센서 네트워크 성능 분석)

  • An, Tea-Ki;Shin, Jeong-Ryol;Kim, Gab-Young;Yang, Se-Hyun;Choi, Gab-Bong;Sim, Bo-Seog
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1701-1708
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    • 2011
  • A typical day in the subway transportation is used by hundreds of thousands are also concerned about the safety of the various workrooms with high underground fire or other less than in the subway users could be damaging even to be raised and there. In 2010, in fact, room air through vents in the fire because smoke and toxic gas accident victims, and train service suspended until such cases are often reported. In response to these incidents in subway stations, even if the latest IT technology, wireless sensor network technology and intelligent video surveillance technology by integrating fire and structural integrity, such as a comprehensive integrated surveillance system to monitor the development of intelligent urban transit system and are under study. In this study, prior to the application of the monitoring system into the field stations, authors carried out the ZigBee-based wireless sensor networks performance analyzation in the Chungmuro station. The test results at a communications room and ventilation room of the station are summarized and analyzed.

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Analysis of Data Encryption Mechanisms for Searchable Encryption (검색가능 암호시스템을 위한 데이터 암호기법의 문제점 분석)

  • Son, Junggab;Yang, Yu-Jin;Oh, Heekuck;Kim, Sangjin
    • Journal of the Korea Society of Computer and Information
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    • v.18 no.9
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    • pp.79-89
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    • 2013
  • Recently, the need for outsourcing sensitive data has grown due to the wide spreading of cost-effective and flexible cloud service. However, there is a fundamental concern in using such service since users have to trust external servers. Therefore, searchable encryption can be a very valuable tool to meet the security requirements of data outsourcing. However, most of work on searchable encryption focus only on privacy preserving search function and relatively lacks research on encryption mechanism used to actually encrypt data. Without a suitable latter mechanism, searchable encryption cannot be deployed in real world cloud services. In this paper, we analyze previously used and possible data encryption mechanisms for multi-user searchable encryption system and discuss their pros and cons. Our results show that readily available tools such as broadcast encryption, attribute-based encryption, and proxy re-encryption do not provide suitable solutions. The main problem with existing tools is that they may require separate fully trusted servers and the difficulty in preventing collusion attacks between outsiders and semi-trusted servers.

Big Deal, Open Access, Google Scholar and the Subscription of Electronic Scholarly Contents at University Libraries (빅딜, 오픈액세스, 구글학술검색과 대학도서관의 전자학술정보구독)

  • Shim, Wonsik
    • Journal of the Korean Society for information Management
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    • v.29 no.4
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    • pp.143-163
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    • 2012
  • The dominant model of acquiring scholarly contents at academic libraries is so called big deal where libraries subscribe to a bundle of hundreds, if not thousands of journals in a multi-year contract with fixed annual rate increase. The bid deal, started in the mid-1990s, offered a number of advantages for academic libraries and their users. However, escalating prices for these packages have become a serious issue casting doubts about the sustainability of the subscription-based model. At the moment, it appears there is no viable alternative other than pay-per-view method that is being tested at some libraries. Libraries' budget situation will remain a key factor that might change the situation. Open access started in the 2000s as a vehicle to eliminate barriers to publishing and distributing peer-reviewed scholarly journal articles. Open access publishing is witnessing two-digit growth annually. Open access articles now occupy close to 20% of two major citation databases: Scopus and Web of Science. Google Scholar service, debuted in late 2004, is now a popular tool for discovering and accessing scholarly articles from a vast selection of journals around the world. There is a call for taking Google Scholar seriously as a potential replacement of library databases amid concerns regarding the quality of journals indexed, limited search capabilities vis-$\grave{a}$-vis library databases, and monopoly of public goods. Escalating budget problems, rapid growth of open access publishing and the emergence of powerful free tool, such as Google Scholar, need to be taken seriously as these forces might bring disruptive changes to the existing subscription-based model of scholarly contents at academic libraries.