• 제목/요약/키워드: quality of channels

검색결과 620건 처리시간 0.026초

APP-MAC-PHY Cross-Layer Video Streaming Technique over Wireless Channels

  • Park, Jaeyoung;Kim, Jaekwon
    • 한국통신학회논문지
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    • 제39A권7호
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    • pp.398-400
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    • 2014
  • In this letter, we propose a cross-layer technique jointly considering modulation coding schemes (MCSs) of medium access control (MAC) layer, source significance information (SSI) and error concealment unit of application (APP) layer, and channel quality information (CQI) of physical (PHY) layer. We demonstrate the improved video quality by the proposed technique when H.264 videos are streamed over Rayleigh fading wireless channels.

악기별 분리처리를 통한 고음질 오디오 시스템 구현 (Implementation of the High-Quality Audio System with the Separately Processed Musical Instrument Channels)

  • 김태훈;이상학;김대경;이상찬
    • 한국음향학회지
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    • 제32권4호
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    • pp.346-353
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    • 2013
  • 본 논문에서는 노래반주기를 위한 고음질 오디오 시스템 구현에 관한 내용을 담고 있다. 노래반주기의 중요한 기능인 키/템포 변환 음질의 개선을 위하여 악기별 채널 분리를 수행하였다. 악기별로 채널을 분리하여 처리함으로 고음질의 변환이 수행됨을 상관계수의 변화와 MOS 평가를 통하여 확인할 수 있었다. 구현된 오디오 시스템은 TI사의 32비트 부동 소수점과 고정 소수점 연산이 모두 가능한 DSP인 TMS320C6747를 이용하였으며 다채널의 WMA 복호화, MP3 부호화와 복호화, wav, EQ 및 템포/키 변환을 실시간으로 수행 가능하다. WMA 10채널로 구성되어 악기별 분리 처리가 가능도록 하였다. 또한 MP3 부호화/복호화는 녹음과 재생 기능으로 이용되고 wav 채널은 효과음 등으로 사용 가능하다.

무선인지시스템을 위한 효율적인 채널 선택 알고리즘 (An Efficient Stochastic Channel Selection Algorithm for Cognitive Radio Networks)

  • 팜티홍츄;구인수
    • 한국인터넷방송통신학회논문지
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    • 제9권6호
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    • pp.29-35
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    • 2009
  • 본 논문에서는 무선인지네트워크를 위한 효율적인 채널 선택 알고리즘을 제안하고 그 성능을 비교분석한다. 제안된 알고리즘에서는 다중의 가용한 채널들 중 최적 채널 선택을 위해 히스토리 윈도우 범위에서 각 채널의 기(primary) 사용자에 의한 채널 사용률 및 성능, 현 채널 품질 그리고 기 사용자의 통계적 트래픽 활동 특성을 고려한다. 시뮬레이션을 통해 무선인지(secondary)사용자들이 제안된 알고리즘을 통하여 다중의 채널들중 데이터 전송을 위한 최적의 채널을 선택할 수 있음을 보였다.

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종합편성채널 식생활관련 프로그램의 식품영양정보 분석 - 전문가 출연자를 중심으로 - (Analysis of Food and Nutrition Information of Diet-related Programs in Comprehensive Programming Channels: Focus on Professional Panelists)

  • 김순미;이선용
    • 한국식생활문화학회지
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    • 제31권6호
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    • pp.661-674
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    • 2016
  • We analyzed information provided by diet-related programs of comprehensive programming channels and the relationship between composition of professional panelists and quality of provided information. We selected 82 items among eight programs by MBN, JTBC, and TV chosun. All 82 items provided information about food & nutrition and health & disease, but only 32 items (39.0%) and 35 items (42.7%) provided information on food culture and food safety, respectively. Among the food ingredients, phytochemicals (81.7%) were the most frequently mentioned, and the contents of functional ingredients occupied a large part. The inappropriate information on programs were broadcast on an average of 1.2 episodes per program, and the most pointed out item was information that could confuse viewers with drugs (29.3%). Among the professional panelists, medical doctors (38.9%) and Oriental medicine doctors (16.6%) had the highest number of appearances, and professors of food & nutrition constituted only 7.1%. However, the increase in the number of appearances of professors showed a positive effect on the quality of program information. Contents focused on balanced nutrient intake and dietary culture of Korea should be increased rather than focusing on the function of each nutrient in comprehensive programming channels.

무선 네트워크에서 신규 호 서비스 향상을 위한 채널할당에 관한 연구 (A Study on the Channel Assignment Scheme on Enhancing New Call Service in Wireless Network)

  • 임영훈
    • 한국통신학회논문지
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    • 제25권9A호
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    • pp.1282-1289
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    • 2000
  • 본 논문에서는 무선 통신망에서 요구되는 핸드오프 호의 차단 확률을 보장하면서 신규 호의 블록킹 확률을 줄이기 위해 트래픽의 변동 특성과 핸드오프 호 비율을 이용한 가변 가드 채널방식을 제안하였다. 제안한 방식에서 핸드오프 발생 비율이 신규 호 발생 비율보다 낮은 경우 채널의 비효율적 사용의 문제점을 개선하기 위하여 정해진 핸드오프 호의 QoS(Quality of Service)를 보장할 수 있는 가드 채널 수를 재 설정한 후 나머지 채널을 신규호에 할당하여 신규 호의 블록킹 확률을 낮출 수 있도록 하였다. 제안한 방식의 성능을 평가하기 위하여 수학적 분석을 하였고 핸드오프 호 차단 확률, 신규 호 블록킹 확률 및 채널 이용률 관점에서 기존의 가드 채널 방식과 비교하였다.

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정보서비스품질이 고객로열티에 미치는 영향에 관한 연구: 고객관계관리 관점 (The Effect of Information Service Quality on Customer Loyalty: A Customer Relationship Management Perspective)

  • 김형수;김승하;김영걸
    • Asia pacific journal of information systems
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    • 제18권1호
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    • pp.1-23
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    • 2008
  • As managing customer relationship gets more important, companies are strengthening information service using multi-channels to their customers as a part of their customer relationship management (CRM) initiatives. It means companies are now accepting such information services not as simple information -delivering tools, but as strategic initiatives for acquiring and maintaining customer loyalty. In this paper, we attempt to validate whether or not such various information services would impact on organizational performance in terms of CRM strategy. More specifically, our research objective is to answer the next three questions: first, how to construct the instruments to measure not information quality but information service quality?; second, which attributes of information service quality can influence corporate image and customer loyalty?; finally, does each information service type have unique characteristics compared with others in terms of influencing corporate image and customer loyalty? With respect to providing answers to those questions, the previous studies had been limited in that those studies failed to consider the variety of types of information service or restricted the quality of information service to information quality. An appropriate research model answering the above questions should consider the fact that most companies are utilizing multi channels for their information services, and include the recent strategic information service such as customer online community. Moreover, since corporate information service could be regarded as a type of products or services delivered to customer, it is necessary to adopt the criteria for assessing customer's perceived value when to measure the quality of information service. Therefore, considering both multi-channels and multi-traits may enable us to tell the detailed causal routes showing which quality attributes of which information service would affect corporate image and customer loyalty. As information service channels, we include not only homepage and DM (direct mail), which are the most frequently applied information service channels, but also online community, which is getting more strategic importance in recent years. With respect to information service quality, we abstract information quality, convenience of information service, and timeliness of information service through a wide range of relevant literature reviews. As our dependant variables, we consider corporate image and customer loyalty that both of them are the critical determinants of organizational performance, and also attempt to grasp the relationship between the two constructs. We conducted a huge online survey at the homepage of one of representative dairy companies in Korea, and gathered 367 valid samples from 407 customers. The reliability and validity of our measurements were tested by using Cronbach's alpha coefficient and principal factor analysis respectively, and seven hypotheses were tested through performing correlation test and multiple regression analysis. The results from data analysis demonstrated that timeliness and convenience of homepage have positive effects on both corporate image and customer loyalty. In terms of DM, its' information quality was represented to influence both corporate image and customer loyalty, but we found its' convenience have a positive effect only on corporate image. With respect to online community, we found its timeliness contribute significantly both to corporate image and customer loyalty. Finally, as we expected, corporate image was revealed to provide a great influence to customer loyalty. This paper provides several academic and practical implications. Firstly, we think our research reinforces CRM literatures by developing the instruments for measuring information service quality. The previous relevant studies have mainly depended on the measurements of information quality or service quality which were developed independently. Secondly, the fact that we conducted our research in a real situation may enable academics and practitioners to understand the effects of information services more clearly. Finally, since our study involved three different types of information service which are most frequently applied in recent years, the results from our study might provide operational guidelines to the companies that are delivering their customers information by multi-channel. In other words, since we found that, in terms of customer loyalty, the key areas would be different from each other according to the types of information services, our analysis would help to make decisions such as selecting strengthening points or allocating resources by information service channels.

사출금형의 냉각채널 성능 평가 (PERFORMANCE EVALUATION OF COOLING CHANNELS IN A PLASTIC INJECTION MOLD MODEL)

  • 김현수;한병윤;이일천;김영만;박형구
    • 한국전산유체공학회지
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    • 제17권2호
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    • pp.53-57
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    • 2012
  • Design of the cooling channels of a plastic injection mold affects the quality and the productivity of the injection processes. In the injection process, the melted resin with high temperature enters the mold cavity, and just after the cavity is filled the heat should be dissipated through the cooling channels simultaneously. The purpose of this study is to analyse the heat transfer phenomenon and to estimate the temperature distribution in the mold to evaluate the cooling effect of the channels. The injection mold is assumed to have cooling channels of circular cross section and each channel has the same coolant flow rate. and The cavity has a rectangular shape. The results show that as the cooling channels get closer to the cavity surface, the cooling efficiency increases as might easily be guessed. However, due to the final hot resin flow from the gate an intensive cooling is required in that region.

옥내 마이크로셀 개인휴대통신 시스템의 채널할당과 핸드오버를 위한 High quality reassignment 방식 (High quality reassignment (HQR) scheme for indoor microcell PCS systems)

  • 오준환;홍대형
    • 전자공학회논문지A
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    • 제33A권2호
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    • pp.40-49
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    • 1996
  • In this paper, we studied channel assignment and handover schemes for the indoor microcell systems. For efficient frequency spectrum reuse we proposed the high quality reassignment (HQR) scheme. Proposed HQR scheme tries to keep the reuse distances small by monitoring C/I of channels being used. To assign a channel for a new or handove call, the scheme checks C/I of all available channels. Then HQR assigns the channel that has C/I near the threshold value, A_TH. The scheme also checks C/I of ongoing calls and continuously reassigns a new channel when needed. It attempts handover not only when C/I gets below a handover threshold value, HO_TH, but also when C/I becomes above a high quality reassignment threshold, H_TH. The performance of the proposed HQR scheme was analyzed by a computer simulation configuraed. The performance of the scheme was also analyzed for various threshold values selected and the results are presented in this paper. The results show that HQR scheme perfomrs better than the scheme adopted for DECT.

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무선 애드혹 통신망용 멀티 채널/라디오 기반 호접속 제어 메저니즘 (Multi-Channel/Radio based CAC Mechanism for Wireless Ad-hoc Networks)

  • 고성원;강민수;김영한
    • 한국정보과학회논문지:정보통신
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    • 제34권5호
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    • pp.396-404
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    • 2007
  • 본 논문에서는 다수의 라디오와 채널을 사용하는 무선 애드혹 통신망에서 대역폭 측정을 기반으로 호 접속 제어와 연동되는 애드혹 라우팅 프로토콜을 제안한다. 단일 라디오에 단일 채널을 사용하는 기존 애드혹 노드와 달리 제안한 MCQosR(Multiple Channel Quality of Service Routing) 프로토콜에서는 각 노드가 다수의 채널과 라디오를 사용하여 노드사이에 전이중 통신을 가능하게 하고 경로의 내부 간섭을 감소시켰다. 또한 각 노드마다 수신전용의 고정된 채널을 갖도록 하였으며, 대역폭 측정을 기반으로 새로운 호에 대한 수락제어를 수행함으로써 QoS 제공을 가능하도록 하였다 제안된 프로토콜은 시뮬레이션을 통하여 성능을 검증하였다.

모바일 고객센터 품질요인이 고객 만족과 신뢰 그리고 고객충성도에 미치는 영향 (The Effect of Mobile Customer Center's Quality Factors on Customer Satisfaction, Trust and Loyalty)

  • 김창수;이인석;유혜인;이성호
    • 한국IT서비스학회지
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    • 제9권3호
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    • pp.1-23
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    • 2010
  • The mobile customer center is one of major customer service channels to gain company's competitive advantage, to establish new correlations between customers and service value, and to respond quickly to customer needs. This study attempted to investigate the effect of mobile customer center's quality on customer satisfaction, trust, and loyalty. For this purpose, we divided quality factors of mobile customer center into mobile service quality and content quality, and then empirically analyzed their impact on customer satisfaction, customer trust, and loyalty. The research result showed mobile service quality and content quality having significant association with customer satisfaction and trust. Moreover, customer satisfaction and trust were closely related to customer loyalty. However, there was no significant difference in the factors affecting customer satisfaction and trust according to the levels of personal innovativeness. It is hoped that this study provides academic foundations for further research on mobile customer center and serves as a useful guideline for operating customer service channels successfully.