• Title/Summary/Keyword: PDA computer

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Intelligent Tutoring System based on Wired and Wireless Internet for the living English 300-certifications Program (생활영어 300 인증제를 대비한 유무선 기반 지능형 교육 시스템)

  • Lee, Young-Seok;Cho, Jung-Won;Kim, Byung-Gyu;Park, Jung-Hwan;Kim, Su-Min;Choi, Byung-Uk
    • Journal of The Korean Association of Information Education
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    • v.9 no.3
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    • pp.533-548
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    • 2005
  • According to the increasing of the internet infrastructure and growth of contents technology, the users can access an education service at anytime and anywhere. In a field of English education, especially, internet technology has enabled learners to communicate with their teachers and multimedia contents technology has been able to provide learner not only lots of interests, but also good effect on English learning. In this paper, we propose a method diagnosing learner's level by using some question-items, which consist of item's type and item's function. Futhermore, the proposed system can support three devices which are PC, PDA, and Mobile Phone on wired and wireless internet communication environments. Also, the system provides multimedia contents including flash movies, image, and audio contents. We have applied the system into real classroom, and we verified that the question-items that system provides has no problem, and our method could improve each learner skill on English education. Therefore, we expect that learner who uses the proposed system will get level-based English learning service at anytime and anywhere.

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An Optimization Technique of Scene Description for Effective Transmission of Interactive T-DMB Contents (대화형 T-DMB 컨텐츠의 효율적인 전송을 위한 장면기술정보 최적화 기법)

  • Li Song-Lu;Cheong Won-Sik;Jae Yoo-Young;Cha Kyung-Ae
    • Journal of Broadcast Engineering
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    • v.11 no.3 s.32
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    • pp.363-378
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    • 2006
  • The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality audio-visual multimedia contents to the mobile environment. The system adopts MPEG-4 standard for the main video, audio and other media format. It also adopts the MPEG-4 scene description for interactive multimedia contents. The animated and interactive contents can be actualized by BIFS(Binary Format for Scene), the binary format for scene description that refers to the spatio-temporal specifications and behaviors of the individual objects. As more interactive contents are, the scene description is also needed more high bitrate. However, the bandwidth for allocating meta data such as scene description is restrictive in mobile environment. On one hand, the DMB terminal starts demultiplexing content and decodes individual media by its own decoder. After decoding each media, rendering module presents each media stream according to the scene description. Thus the BIFS stream corresponding to the scene description should be decoded and parsed in advance of presenting media data. With these reason, the transmission delay of BIFS stream causes the delay of whole audio-visual scene presentation although the audio or video streams are encoded in very low bitrate. This paper presents the effective optimization technique for adapting BIFS stream into expected MPEG-2 TS bitrate without any bandwidth waste and avoiding the transmission delay of the initial scene description for interactive DMB contents.

차세대 Embedded 마이크로프로세서 기술 동향

  • Lee, Hui
    • The Magazine of the IEIE
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    • v.28 no.7
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    • pp.49-55
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    • 2001
  • 1970년대에 개발된 마이크로 프로세서는 제어기기 분야 및 소형 컴퓨터에서 주로 사용되어 오다가 1980년대에 이르러 RISC(Reduced Instruction Set Computer) 구조의 도입으로 중대형 컴퓨터에 이르기까지 광범위하게 사용되고 있다. 또한 반도체 기술의 급격한 발전으로 슈퍼스칼라 구조가 마이크로 프로세서에서도 적용되고 있으며 동작 속도도 수백 MHz에 이르고 있다. 마이크로 프로세서는 프로그램을 수행하기 위해서 프로그램과 데이터를 메모리로부터 읽어 와야 한다. 그런데 메모리 용량은 빠른 속도로 증가하고 있지만 동작 속도는 마이크로 프로세서의 동작 속도에 크게 미치지 못하고 있다. 1980년에 DRAM의 접근 속도는 250nsec이었으나 1998년에 RDRAM의 동작속도는 300MHz로 70여배 빨라졌다. 그러나 마이크로프로세서는 1980년에 8086의 동작 속도가 8MHz이던 것이 1998년에는 팬티엄-2가 500MHz에 이르고 있다. 더욱이 팬티엄-2는 슈퍼스칼라 구조이므로 이를 감안하면 1GHz 이상에 이르러 120여 배 빨라진 것을 알 수 있다. 이와 같은 메모리 속도와 마이크로 프로세서 속도 차이에 더하여, 메모리와 마이크로 프로세서를 인쇄 회로 기판에서 연결하는데 따른 물리적 특성은 변화하지 않으므로 데이터 전송 폭을 넓히는 것에는 한계가 있다. 따라서 향후 컴퓨터 성능 발달을 제한하는 주요 요소 중 하나는 마이크로 프로세서와 메모리 사이의 데이터 전송 폭이다. 프로그램과 데이터가 메모리에 저장되는 본 뉴먼 방식의 컴퓨터에서 데이터 전송 폭을 줄이기 위해서는 코드 밀도(Code Density)가 높은 컴퓨터 구조를 연구하는 것이 필요하다. 한편 마이크로 프로세서는 실장 제어용으로 거의 모든 전자 제품 및 자동화 기기에서 채용하고 있다. 특히 냉장고, 에어콘, 전축, TV, 세탁기 등 가전기기와 Fax, 복사기, 프린터 등 사무용기기와 자동차, 선박, 자동화기계 등 사무 및 산업용 기기와 PDA(휴대용 정보 기기), NC(Network Computer) 등 정보 기기 그리고 각종 오락기, 노래 반주지 등 정보 기기 등에서 사용하는 실장 제어용 마이크로 프로세서 시장은 매년 10% 이상씩 성장하고 있으며, 21세기 산업을 주도하는 핵심 기술로 자리 매김하고 있다. 이러한 실장 제어용 기기는 마이크로 프로세서와 메모리 및 입출력 자이가 하나의 반도체에 집적되는 경우가 많다. 그런데 반도체 가격은 반도체 크기에 따라 결정되며, 가장 넓은 면적을 차지하는 것은 메모리이다. 따라서 반도체 가격을 낮추기 위해서는 메모리 크기를 줄여야 하며, 이를 위해서 또한 코드 밀도가 높은 컴퓨터 구조에 대한 연구가 필요하다. 최근에는 322비트 RISC 명령어를 16비트 명령어로 축약한 구조가 연구되었다. ARM-7TDMI는 ARM-7의 16비트 축약 명령어 구조이며, TR4101은 MIPS-R3000의 16비트 축약 명령어 구조이다. 이들 16비트 축약 명령어 RISC는 종래 RISC와의 호환성을 위하여 2가지 모드로 동작하므로 구조가 복잡하고, 16비트 명령어에서는 8개의 레지스타만을 접근할 수 있으므로 성능이 크게 떨어지는 단점을 가진다.

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A Key Management Scheme without Re-encryption for Home-domain Contents Distribution in Open IPTV Environments (Open IPTV 환경에서 재암호화 과정 없는 댁내 컨텐츠 분배를 위한 키관리 기법)

  • Jung, Seo-Hyun;Roh, Hyo-Sun;Lee, Hyun-Woo;Yi, Jeong-Hyun;Jung, Sou-Hwan
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.7
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    • pp.57-66
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    • 2010
  • Due to the advancement of IPTV technologies, open IPTV services are a step closer to becoming reality. In such service environment, users are able to enjoy IPTV services using a variety of devices available at their home domain. However, it is impossible to get such flexible services at their convenience unless each of devices is individually connected to Set-Top-Box (STB) because of Conditional Access System (CAS) or service providers otherwise allow STB to freely distribute decoded contents to every user devices attached to STB. In this paper, we propose a key management scheme for securely distributing contents from STB to multiple user devices at home domain. The proposed scheme also makes the service providers be able to control the access rights to each of user devices without installing individual STBs. It is achieved by computationally dividing a private key of RSA signature scheme into three parts and thus makes possible to distribute the contents scrambled through a underlying CAS mechanism without re-encrypting them that the existing scheme should employ. It improves significantly computation and communication complexities, maintaining it as secure as the existing schemes. Additionally, it prevents misbehaving users from illegally distributing the contents from STB to their devices available at home domain.

Development Plan of Guard Service According to the LBS Introduction (경호경비 발전전략에 따른 위치기반서비스(LBS) 도입)

  • Kim, Chang-Ho;Chang, Ye-Chin
    • Korean Security Journal
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    • no.13
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    • pp.145-168
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    • 2007
  • Like to change to the information-oriented society, the guard service needs to be changed. The communication and hardware technology develop rapidly and according to the internet environment change from cable to wireless, modern person can approach every kinds of information service using wireless communication machinery which can be moved such as laptop, computer, PDA, mobile phone and so on, LBS field which presents the needing information and service at anytime, anywhere, and which kinds of device expands it's territory all the more together with the appearance of ubiquitous concept. LBS use the chip in the mobile phone and make to confirm the position of the joining member anytime within several tens centimeters to hundreds meters. LBS can be divided by the service method which use mobile communication base station and apply satellite. Also each service type can be divided by location chase service, public safe service, location based information service and so on, and it is the part which will plan with guard service development. It will be prospected 8.460 hundred million in 2005 years and 16.561 hundred million in 2007 years scale of market. Like this situation, it can be guessed that the guard service has to change rapidly according to the LBS application. Study method chooses documentary review basically, and at first theory method mainly uses the second documentary examination which depends on learned journal and independent volume which published in the inside and the outside of the country, internet searching, other kinds of all study report, statute book, thesis which published at public order research institute of the Regional Police Headquarter, police operation data, data which related with statute, documents and statistical data which depend on private guard company and so on. So the purpose of the study gropes in accordance with the LBS application, and present the problems and improvement method to analyze indirect of manager side of operate guard adaptation service of LBS, government side which has to activate LBS, systematical, operation management, manpower management and education training which related with guard course side which has to study and educate in accordance with application of the new guard service, as well as intents to excellent quality service of guard.

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An Algorithm for Managing Storage Space to Maximize the CPU Availability in VOD Systems (VOD 시스템에서 CPU 가용성을 최대화하는 저장공간관리 알고리즘)

  • Jung, Ji-Chan;Go, Jae-Doo;Song, Min-Seok;Sim, Jeong-Seop
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.3
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    • pp.140-148
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    • 2009
  • Recent advances in communication and multimedia technologies make it possible to provide video-on-demand(VOD) services and people can access video servers over the Internet at any time using their electronic devices, such as PDA, mobile phone and digital TV. Each device has different processing capabilities, energy budgets, display sizes and network connectivities. To support such diverse devices, multiple versions of videos are needed to meet users' requests. In general cases, VOD servers cannot store all the versions of videos due to the storage limitation. When a device requests a stored version, the server can send the appropriate version immediately, but when the requested version is not stored, the server first converts some stored version to the requested version, and then sends it to the client. We call this conversion process transcoding. If transcoding occurs frequently in a VOD server, the CPU resource of the server becomes insufficient to response to clients. Thus, to admit as many requests as possible, we need to maximize the CPU availability. In this paper, we propose a new algorithm to select versions from those stored on disk using a branch and bound technique to maximize the CPU availability. We also explore the impact of these storage management policies on streaming to heterogeneous users.

Power Conscious Disk Scheduling for Multimedia Data Retrieval (저전력 환경에서 멀티미디어 자료 재생을 위한 디스크 스케줄링 기법)

  • Choi, Jung-Wan;Won, Yoo-Jip;Jung, Won-Min
    • Journal of KIISE:Computer Systems and Theory
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    • v.33 no.4
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    • pp.242-255
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    • 2006
  • In the recent years, Popularization of mobile devices such as Smart Phones, PDAs and MP3 Players causes rapid increasing necessity of Power management technology because it is most essential factor of mobile devices. On the other hand, despite low price, hard disk has large capacity and high speed. Even it can be made small enough today, too. So it appropriates mobile devices. but it consumes too much power to embed In mobile devices. Due to these motivations, in this paper we had suggested methods of minimizing Power consumption while playing multimedia data in the disk media for real-time and we evaluated what we had suggested. Strict limitation of power consumption of mobile devices has a big impact on designing both hardware and software. One difference between real-time multimedia streaming data and legacy text based data is requirement about continuity of data supply. This fact is why disk drive must persist in active state for the entire playback duration, from power management point of view; it nay be a great burden. A legacy power management function of mobile disk drive affects quality of multimedia playback negatively because of excessive I/O requests when the disk is in standby state. Therefore, in this paper, we analyze power consumption profile of disk drive in detail, and we develop the algorithm which can play multimedia data effectively using less power. This algorithm calculates number of data block to be read and time duration of active/standby state. From this, the algorithm suggested in this paper does optimal scheduling that is ensuring continual playback of data blocks stored in mobile disk drive. And we implement our algorithms in publicly available MPEG player software. This MPEG player software saves up to 60% of power consumption as compared with full-time active stated disk drive, and 38% of power consumption by comparison with disk drive controlled by native power management method.

Perceptional Change of a New Product, DMB Phone

  • Kim, Ju-Young;Ko, Deok-Im
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.3
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    • pp.59-88
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    • 2008
  • Digital Convergence means integration between industry, technology, and contents, and in marketing, it usually comes with creation of new types of product and service under the base of digital technology as digitalization progress in electro-communication industries including telecommunication, home appliance, and computer industries. One can see digital convergence not only in instruments such as PC, AV appliances, cellular phone, but also in contents, network, service that are required in production, modification, distribution, re-production of information. Convergence in contents started around 1990. Convergence in network and service begins as broadcasting and telecommunication integrates and DMB(digital multimedia broadcasting), born in May, 2005 is the symbolic icon in this trend. There are some positive and negative expectations about DMB. The reason why two opposite expectations exist is that DMB does not come out from customer's need but from technology development. Therefore, customers might have hard time to interpret the real meaning of DMB. Time is quite critical to a high tech product, like DMB because another product with same function from different technology can replace the existing product within short period of time. If DMB does not positioning well to customer's mind quickly, another products like Wibro, IPTV, or HSPDA could replace it before it even spreads out. Therefore, positioning strategy is critical for success of DMB product. To make correct positioning strategy, one needs to understand how consumer interprets DMB and how consumer's interpretation can be changed via communication strategy. In this study, we try to investigate how consumer perceives a new product, like DMB and how AD strategy change consumer's perception. More specifically, the paper segment consumers into sub-groups based on their DMB perceptions and compare their characteristics in order to understand how they perceive DMB. And, expose them different printed ADs that have messages guiding consumer think DMB in specific ways, either cellular phone or personal TV. Research Question 1: Segment consumers according to perceptions about DMB and compare characteristics of segmentations. Research Question 2: Compare perceptions about DMB after AD that induces categorization of DMB in direction for each segment. If one understand and predict a direction in which consumer perceive a new product, firm can select target customers easily. We segment consumers according to their perception and analyze characteristics in order to find some variables that can influence perceptions, like prior experience, usage, or habit. And then, marketing people can use this variables to identify target customers and predict their perceptions. If one knows how customer's perception is changed via AD message, communication strategy could be constructed properly. Specially, information from segmented customers helps to develop efficient AD strategy for segment who has prior perception. Research framework consists of two measurements and one treatment, O1 X O2. First observation is for collecting information about consumer's perception and their characteristics. Based on first observation, the paper segment consumers into two groups, one group perceives DMB similar to Cellular phone and the other group perceives DMB similar to TV. And compare characteristics of two segments in order to find reason why they perceive DMB differently. Next, we expose two kinds of AD to subjects. One AD describes DMB as Cellular phone and the other Ad describes DMB as personal TV. When two ADs are exposed to subjects, consumers don't know their prior perception of DMB, in other words, which subject belongs 'similar-to-Cellular phone' segment or 'similar-to-TV' segment? However, we analyze the AD's effect differently for each segment. In research design, final observation is for investigating AD effect. Perception before AD is compared with perception after AD. Comparisons are made for each segment and for each AD. For the segment who perceives DMB similar to TV, AD that describes DMB as cellular phone could change the prior perception. And AD that describes DMB as personal TV, could enforce the prior perception. For data collection, subjects are selected from undergraduate students because they have basic knowledge about most digital equipments and have open attitude about a new product and media. Total number of subjects is 240. In order to measure perception about DMB, we use indirect measurement, comparison with other similar digital products. To select similar digital products, we pre-survey students and then finally select PDA, Car-TV, Cellular Phone, MP3 player, TV, and PSP. Quasi experiment is done at several classes under instructor's allowance. After brief introduction, prior knowledge, awareness, and usage about DMB as well as other digital instruments is asked and their similarities and perceived characteristics are measured. And then, two kinds of manipulated color-printed AD are distributed and similarities and perceived characteristics for DMB are re-measured. Finally purchase intension, AD attitude, manipulation check, and demographic variables are asked. Subjects are given small gift for participation. Stimuli are color-printed advertising. Their actual size is A4 and made after several pre-test from AD professionals and students. As results, consumers are segmented into two subgroups based on their perceptions of DMB. Similarity measure between DMB and cellular phone and similarity measure between DMB and TV are used to classify consumers. If subject whose first measure is less than the second measure, she is classified into segment A and segment A is characterized as they perceive DMB like TV. Otherwise, they are classified as segment B, who perceives DMB like cellular phone. Discriminant analysis on these groups with their characteristics of usage and attitude shows that Segment A knows much about DMB and uses a lot of digital instrument. Segment B, who thinks DMB as cellular phone doesn't know well about DMB and not familiar with other digital instruments. So, consumers with higher knowledge perceive DMB similar to TV because launching DMB advertising lead consumer think DMB as TV. Consumers with less interest on digital products don't know well about DMB AD and then think DMB as cellular phone. In order to investigate perceptions of DMB as well as other digital instruments, we apply Proxscal analysis, Multidimensional Scaling technique at SPSS statistical package. At first step, subjects are presented 21 pairs of 7 digital instruments and evaluate similarity judgments on 7 point scale. And for each segment, their similarity judgments are averaged and similarity matrix is made. Secondly, Proxscal analysis of segment A and B are done. At third stage, get similarity judgment between DMB and other digital instruments after AD exposure. Lastly, similarity judgments of group A-1, A-2, B-1, and B-2 are named as 'after DMB' and put them into matrix made at the first stage. Then apply Proxscal analysis on these matrixes and check the positional difference of DMB and after DMB. The results show that map of segment A, who perceives DMB similar as TV, shows that DMB position closer to TV than to Cellular phone as expected. Map of segment B, who perceive DMB similar as cellular phone shows that DMB position closer to Cellular phone than to TV as expected. Stress value and R-square is acceptable. And, change results after stimuli, manipulated Advertising show that AD makes DMB perception bent toward Cellular phone when Cellular phone-like AD is exposed, and that DMB positioning move towards Car-TV which is more personalized one when TV-like AD is exposed. It is true for both segment, A and B, consistently. Furthermore, the paper apply correspondence analysis to the same data and find almost the same results. The paper answers two main research questions. The first one is that perception about a new product is made mainly from prior experience. And the second one is that AD is effective in changing and enforcing perception. In addition to above, we extend perception change to purchase intention. Purchase intention is high when AD enforces original perception. AD that shows DMB like TV makes worst intention. This paper has limitations and issues to be pursed in near future. Methodologically, current methodology can't provide statistical test on the perceptual change, since classical MDS models, like Proxscal and correspondence analysis are not probability models. So, a new probability MDS model for testing hypothesis about configuration needs to be developed. Next, advertising message needs to be developed more rigorously from theoretical and managerial perspective. Also experimental procedure could be improved for more realistic data collection. For example, web-based experiment and real product stimuli and multimedia presentation could be employed. Or, one can display products together in simulated shop. In addition, demand and social desirability threats of internal validity could influence on the results. In order to handle the threats, results of the model-intended advertising and other "pseudo" advertising could be compared. Furthermore, one can try various level of innovativeness in order to check whether it make any different results (cf. Moon 2006). In addition, if one can create hypothetical product that is really innovative and new for research, it helps to make a vacant impression status and then to study how to form impression in more rigorous way.

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