• Title/Summary/Keyword: multimedia data

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Service Differentiation in Ad Hoc Networks by a Modified Backoff Algorithm (애드혹 네트워크 상에서 backoff 알고리즘 수정에 의한 서비스 차별화)

  • Seoung-Seok Kang;Jin Kim
    • Journal of KIISE:Information Networking
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    • v.31 no.4
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    • pp.414-428
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    • 2004
  • Many portable devices are coming to be commercially successful and provide useful services to mobile users. Mobile devices may request a variety of data types, including text and multimedia data, thanks to the rich content of the Internet. Different types of data and/or different classes of users may need to be treated with different qualities of service. The implementation of service differentiation in wireless networks is very difficult because of device mobility and wireless channel contention when the backoff algorithm is used to resolve contention. Modification of the t)mary exponential backoff algorithm is one possibility to allow the design of several classes of data traffic flows. We present a study of modifications to the backoff algorithm to support three classes of flows: sold, silver, and bronze. For example, the gold c]ass flows are the highest priority and should satisfy their required target bandwidth, whereas the silver class flows should receive reasonably high bandwidth compared to the bronze class flows. The mixture of the two different transport protocols, UDP and TCP, in ad hoc networks raises significant challenges when defining backoff algorithm modifications. Due to the different characteristics of UDP and TCP, different backoff algorithm modifications are applied to each class of packets from the two transport protocols. Nevertheless, we show by means of simulation that our approach of backoff algorithm modification clearly differentiates service between different flows of classes regardless of the type of transport protocol.

An Analysis of Image Use in Twitter Message (트위터 상의 이미지 이용에 관한 분석)

  • Chung, EunKyung;Yoon, JungWon
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.24 no.4
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    • pp.75-90
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    • 2013
  • Given the context that users are actively using social media with multimedia embedded information, the purpose of this study is to demonstrate how images are used within Twitter messages, especially in influential and favorited messages. In order to achieve the purpose of this study, the top 200 influential and favorited messages with images were selected out of 1,589 tweets related to "Boston bombing" in April 2013. The characteristics of the message, image use, and user are analyzed and compared. Two phases of the analysis were conducted on three data sets containing the top 200 influential messages, top 200 favorited messages, and general messages. In the first phase, coding schemes have been developed for conducting three categorical analyses: (1) categorization of tweets, (2) categorization of image use, and (3) categorization of users. The three data sets were then coded using the coding schemes. In the second phase, comparison analyses were conducted among influential, favorited, and general tweets in terms of tweet type, image use, and user. While messages expressing opinion were found to be most favorited, the messages that shared information were recognized as most influential to users. On the other hand, as only four image uses - information dissemination, illustration, emotive/persuasive, and information processing - were found in this data set, the primary image use is likely to be data-driven rather than object-driven. From the perspective of users, the user types such as government, celebrity, and photo-sharing sites were found to be favorited and influential. An improved understanding of how users' image needs, in the context of social media, contribute to the body of knowledge of image needs. This study will also provide valuable insight into practical designs and implications of image retrieval systems or services.

A study on the Domestic Consumer's Perception of "Hansik" with Big Data Analysis : Using Text Mining and Semantic Network Analysis (빅데이터를 통한 내국인의 '한식' 인식 연구 : 텍스트마이닝과 의미연결망 중심으로)

  • Park, Kyeong-Won;Yun, Hee-Kyoung
    • Journal of the Korea Convergence Society
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    • v.11 no.6
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    • pp.145-151
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    • 2020
  • 'Hansik', or Korean cuisine is one of Korea national brands. To understand the domestic consumer awareness of Korean cuisine, data was gathered under the keyword search, 'Hansik.' Textom 3.5 was used to gather data from blogs, news media found on Naver from November 1, 2018, to October 31, 2019. The results from frequency and TF-IDF analysis indicate that the 'buffet' had the largest proportion in terms of consumer awareness to Hansik. Also, broadcasting contents starring star chefs had a great influence. The Hansik awareness did not remain in the domains of its traditionality, but also branched into extents into areas such as fusional and gourmet cuisine. UCINET6 and NetDraw were used to conduct CONCOR analysis. Four cluster formations have been found; various food cultural cluster, high-end restaurant cluster referring to aired restaurants on media, Hansik brand cluster, and Hansik buffet cluster. This study proposes presenting a various menu of Hansik which use a multiple number of ingredients. Also, a promotion that introduces fine Hansik and a development of marketing views and media contents about the convenient HMRs make the associated imagery of Hansik to be strengthen.

An Adaptive Packet Loss Recovery Scheme for Realtime Data in Mobile Computing Environment (이동 컴퓨팅 환경에서 실시간 데이터의 적응적 손실 복구 방법)

  • Oh, Yeun-Joo;Baek, Nak-Hoon;Park, Kwang-Roh;Jung, Hae-Won;Lim, Kyung-Shik
    • Journal of KIISE:Information Networking
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    • v.28 no.3
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    • pp.389-405
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    • 2001
  • In these days, we have increasing demands on the real-time services, especially for the multimedia data transmission in both of wired and wireless environments and thus efficient and stable ways of transmitting realtime data are needs. Although RTP is widely used for internet-based realtime applications, it cannot avoid packet losses, due to the use of UDP stack and its underlying layers. In the case of mobile computing applications, the packet losses are more frequent and consecutive because of the limited bandwidth. In this paper, we first statistically analyze the characteristics of packet losses in the wired and wireless communications, based on Gilbert model, and a new packet recovery scheme for realtime data transmission is presented. To reflect the transmission characteristics of the present network environment, our scheme makes the sender to dynamically adjust the amount of redundant information, using the current packet loss characteristic parameters reported by the receiver. Additionally, we use relatively large and discontinuous offset values, which enables us to recover from both of the random and consecutive packet losses. Due to these characteristics, our scheme is suitable for the mobile computing environment where packet loss rates are relatively high and varies rapidly in a wide range. Since our scheme is based on the analytic model form statistics, it can also be used for other network environments. We have implemented the scheme with Mobile IP and RTP/RTCP protocols to experimentally verify its efficiency.

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Measurement and Analysis of Performance to Transfer Data in a Wireless-Cum-Wired Intra-Network (유무선 통합 인트라넷 환경에서 데이터 전송 성능 측정 및 분석)

  • Hur Hye-Sun;Hong Youn-Sik;Woo Yo-Seop
    • Journal of Internet Computing and Services
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    • v.5 no.3
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    • pp.99-108
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    • 2004
  • We have designed and implemented a Voice Messenger System(VMS) for sending and receiving voice data in order to measure and analyze the performance of a multimedia data transfer system using PDAs(Personal Digital Assistants) in a fast wireless LAN environment. The VMS has been configured as an infrastructure network by integrating a wireless intra-network based on IEEE 802,11 b standard with a wired network based on Ethernet. A sending time, a receiving time and a round-trip time(RTT) have been measured by varying its pecket size from 256 to 6656 bytes, Besides, we have performed the experiments to see which NIC is more stable between CF and PCMCIA type in such a wireless LAN environment, The results of such experiments show that the NIC with PCMClA type is better than that with CF type from the points of both efficiency and stability. The performance of a notebook computer with the attachment of a wireless NIC that is used as a VMS client is almost constant by varying its packet size when transferring voice data. However, with PDA client, in the case of receiving packets from the VMS server, the performance is the best when the pecket size is 6656 bytes, In addition, in the case of sending packets from PDA client to the VMS server, the performance is the best when the packet size is 4096 bytes. Even with the same pecket size, the time of receiving packets from the VMS server to PDA is longer than the time of sending packets from PDA to the VMS Server, Thus, we conclude that when PDA is used as a client by applying different pecket size when sending and receiving packets should be achieved a better performance over a wireless LAN environment.

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Compact Field Remapping for Dynamically Allocated Structures (동적으로 할당된 구조체를 위한 압축된 필드 재배치)

  • Kim, Jeong-Eun;Han, Hwan-Soo
    • Journal of KIISE:Software and Applications
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    • v.32 no.10
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    • pp.1003-1012
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    • 2005
  • The most significant difference of embedded systems from general purpose systems is that embedded systems are allowed to use only limited resources including battery and memory. Especially, the number of applications increases which deal with multimedia data. In those systems with high data computations, the delay of memory access is one of the major bottlenecks hurting the system performance. As a result, many researchers have investigated various techniques to reduce the memory access cost. Most programs generally have locality in memory references. Temporal locality of references means that a resource accessed at one point will be used again in the near future. Spatial locality of references is that likelihood of using a resource gets higher if resources near it were just accessed. The latest embedded processors usually adapt cache memory to exploit these two types of localities. Processors access faster cache memory than off-chip memory, reducing the latency. In this paper we will propose the enhanced dynamic allocation technique for structure-type data in order to eliminate unused memory space and to reduce both the cache miss rate and the application execution time. The proposed approach aggregates fields from multiple records dynamically allocated and consecutively remaps them on the memory space. Experiments on Olden benchmarks show $13.9\%$ L1 cache miss rate drop and $15.9\%$ L2 cache miss drop on average, compared to the previously proposed techniques. We also find execution time reduced by $10.9\%$ on average, compared to the previous work.

Energy-efficient Correlated Data Placement Techniques for Multi-disk-based Mobile Systems (다중 디스크 기반 모바일 시스템 대상의 에너지 효율적인 연관 데이타 배치 기법)

  • Kim, Young-Jin;Kwon, Kwon-Taek;Kim, Ji-Hong
    • Journal of KIISE:Computer Systems and Theory
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    • v.34 no.3
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    • pp.101-112
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    • 2007
  • Hard disks have been the most prevalent secondary storage devices and these days their usage is becoming more important in mobile computing systems due to I/O intensive applications such as multimedia applications and games. However, significant power consumption in the disk drives still limits battery lifetimes of mobile systems critically. In this paper, we show that using several smaller disks (instead of one large disk) can be an energy-efficient secondary storage solution on typical mobile platforms without a significant performance delay. Also, we propose a novel energy-efficient technique, which clusters related data into groups and migrates the correlated groups to the same disk. We compare this method with the existing data concentration scheme, and also combine them. The experiments show that our technique saves the energy consumption up to 34% when a pair of 1.8' disks is used instead of a single 2.5' disk with a negligible increase in the average response time. The results also show that our method also saves up to 14.8% of disk energy consumption and improve the average I/O response time by up to 10 times over the existing scheme.

A Multicast Middleware for the Remote Educational Systems (원격 교육 시스템을 위한 멀티캐스트 미들웨어)

  • Byun, Sang-Seon;Jin, Hyun-Wook;Yoo, Hyuck
    • Journal of KIISE:Computing Practices and Letters
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    • v.9 no.1
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    • pp.100-108
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    • 2003
  • By choosing Multicast for transmission of educational contents in the Remote Educational System, we can reduce the server load and increase network bandwidth utilization. We design and implement Multicast Middleware for the Remote Educational System in this paper. There are three characteristics in this Multicast Middleware: 1) Through Centralized Multicast Group Management for passive members, it allows a host to make multicast group, which is composed of receivers, called Group Member and who are chosen by the host, called group Maker. Because, all groups are created by the Group Maker in Centralized Group Management, Group Member's join action will be passive 2) Maintenance and recovery of multicast group information in order to restore from exception and crash; the maintenance and recovery mechanism of Group Maker is distinct from that of Group Member. 3) The mechanism which enables to transmit large size multimedia data through multicasting and remove additional copy operation through shared buffer. Fragmentation/de-fragmentation for large data delivery results in additional copy operation in user level. But by using user level shared buffer, it can be done without user Bevel copy operation. By applying to Remote Educational environment which consists of 30 PCs and Fast Ethernet, we can examine the efficiency of this middleware, which can transmit 18frames/sec movie which resolution 320 $\times$ 120 pixels, 128Kbps encoded sound data and some text data.

Open GIS Component Software Ensuring an Interoperability of Spatial Information (공간정보 상호운용성 지원을 위한 컴포넌트 기반의 개방형 GIS 소프트웨어)

  • Choe, Hye-Ok;Kim, Gwang-Su;Lee, Jong-Hun
    • The KIPS Transactions:PartD
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    • v.8D no.6
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    • pp.657-664
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    • 2001
  • The Information Technology has progressed to the open architecture, component, and multimedia services under Internet, ensuring interoperability, reusability, and realtime. The GIS is a system processing geo-spatial information such as natural resources, buildings, roads, and many kinds of facilities in the earth. The spatial information featured by complexity and diversity requires interoperability and reusability of pre-built databases under open architecture. This paper is for the development of component based open GIS Software. The goal of the open GIS component software is a middleware of GIS combining technology of open architecture and component ensuring interoperability of spatial information and reusability of elementary pieces of GIS software. The open GIS component conforms to the distributed open architecture for spatial information proposed by OGC (Open GIS Consortium). The system consists of data provider components, kernel (MapBase) components, clearinghouse components and five kinds of GIS application of local governments. The data provider component places a unique OLE DB interface to connect and access diverse data sources independent of their formats and locations. The MapBase component supports core and common technology of GIS feasible for various applications. The clearinghouse component provides functionality about discovery and access of spatial information under Internet. The system is implemented using ATL/COM and Visual C++ under MicroSoft's Windows environment and consisted of more than 20 components. As we made case study for KSDI (Korea Spatial Data Infrastructure) sharing spatial information between local governments, the advantage of component based open GIS software was proved. Now, we are undertaking another case study for sharing seven kinds of underground facilities using the open GIS component software.

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A Study on Design of Annotation Database for Visible Human (인체영상 어노테이션 DB 설계에 관한 연구)

  • Ahn, bu-young;Lee, seung-bock;Han, Geon;Lee, sang-ho
    • Proceedings of the Korea Contents Association Conference
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    • 2008.05a
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    • pp.819-822
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    • 2008
  • As the IT and computer network technology is developed very rapidly, the quantity of digital contents is increased and disseminated more widely. The digital contents is generally expressed in 2 or 3 dimensional multimedia format and the visible human image that is taken from human body is very important because of its variety of usefulness. The KISTI(Korea Institute of Science and Technology Information) is now constructing various Korean human informations such as visible Korean, digital Korean, human bone property and human models. These informations are accessable through the internet. However, these human images are not easily understandable for general users because they are specialized in medical image field and there is no detailed explanation data. In this study, we designed the annotation database and searching interface for KISTI's visible Korean database. This annotation database involved the detailed explanation and special note of visible Korean data and it can connect the image and text data of visible Korean with each other. By studying this database and interface design, the KISTI's visible Korean database is more easily accessable and understandable to general users and it can promote the usage of visible Korean data more widely.

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