• The KIPS Transactions:PartD
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• v.11D no.2
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• pp.339-350
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• 2004

A broadcast method in mobile computing environments which have very large client populations solves the problem of low bandwidth. But most of previous proposed concurrency control protocols are restricted to read-only transactions from mobile client. In this paper, we propose the UTSM-ARM method which uses caching and broadcast method, and allows update transactions in mobile client. The UTSM-ARM decides the validation of cache data consistency with the dynamic update pattern ratio of accessed cached data. Also, the timestamps of accessed cached data and transaction in mobile client guarantee the serializable execution of mobile transactions. As a result, UTSM-ARM makes efficiently use of the asymmetric bandwidth of broadcast environment and can Increase the transaction throughput.

• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.33-39
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• 2014

How to transfer spatial data from server to client in wireless broadcasting environment is shown as following: A server arranges data information that client wants and transfers data by one-dimensional array for broadcasting cycle. Client listens data transferred by the server and returns resulted value only to server. Recently number of users using location-based services is increasing alongside number of objects, and data volume is changing into large amount. Large volume of data in wireless broadcasting environment may increase query time of client. Therefore, we propose Client based Data Scheduling (CDS) for efficient data scheduling in wireless broadcasting environment. CDS divides map and then calculates total sum of objects for each grid by considering number of objects and data size within divided grids. It carries out data scheduling by applying hot-cold method considering total data size of objects for each grid and number of client. It's proved that CDS reduces average query processing time for client compared to existing method.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.315-322
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• 2023

Intelligent IoT environments that accommodate a very large number of clients require technologies that provide secure information service regardless of the number of clients. Wireless data broadcast is an information service technique that ensures scalability to deliver data to all clients simultaneously regardless of the number of clients. In wireless data broadcasting, clients access the wireless channel linearly to explore the data, so the access time of clients is greatly affected by the broadcast cycle. Data compression-based data broadcasting can reduce the broadcast cycle and thus reduce client access time. Therefore, a simulation framework that can evaluate the performance of data broadcasting by applying different data compression algorithms is essential and important. In this paper, we propose a simulation framework to evaluate the performance of data broadcasting that can adopt data compression. We design the framework that enables to apply different data compression algorithms according to the data characteristics. In addition to evaluating the performance according to the data, the proposed framework can also evaluate the performance according to the data scheduling technique and the kind of queries the client wants to process. We implement the proposed framework and evaluate the performance of data broadcasting using the framework applying data compression algorithms to demonstrate the performances of data compression broadcasting.

• The KIPS Transactions:PartB
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• v.11B no.7 s.96
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• pp.803-812
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• 2004

The performance of video-on-demand(VOD) systems is known to be mainly dependent on a scheduling mechanism which they employ. Broadcast-based scheduling schemes have attracted a lot of attention as an efficient way of distributing popular videos to very large client populations. The main motivations of broadcasting scheduling mechanisms are that they scale up extremely well and they have very modest bandwidth requirements. This paper studies this issue and proposes a new broadcasting scheduling mechanism, named fast universal video dis-tribution(FUVD). FUVD scheme dynamically constructs a video broadcasting schedule in response to client requests, and broadcasts video seg-ments according to this schedule. This paper also evaluates the performance of FUVD on the basis of a simulation approach. The simulation results indicate that FUVD protocol shows a superior performance over UD, CBHD, and NPB in terms of the average response time.

• International journal of advanced smart convergence
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• v.7 no.4
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• pp.10-18
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• 2018

For the information services supporting requests of data items from a great number of mobile clients, wireless data broadcasting is an effective way because it can accommodate any number of clients. In the wireless data broadcasting, various air indexing schemes and data scheduling schemes have been developed in order to enable the clients to access their desired data items efficiently. The broadcasting system needs a method to simulate newly designed air indexing and scheduling schemes of the system, and to evaluate the performance parameters of the schemes. In this paper, we design an expandable and efficient simulation framework for the wireless data broadcasting based on the partition of data ID space. The framework can adopt regular and irregular space partition and evaluate various performance parameters of the broadcasting system. We implement a testbed of the broadcasting system using the framework, that adopts IIP, GDI and EXP as its air indexing schemes. We simulate the system using the testbed and evaluate the performance parameters of the system. Thus, we show the efficiency and expandability of the designed and implemented framework.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.364-365
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• 2016

컴퓨터 생성 홀로그램(CGH)는 방대한 계산 량을 가지고 있어, 고해상도의 홀로그램을 생성하기 위하여 고속 홀로그램 생성 방법이 필요하다. 본 논문에서는 다중 GPGPU의 스케쥴링 기법을 이용하여 고속화 하는 방법을 제안한다. 첫 번째로는 커널 내에서 공유 메모리를 이용한 스케쥴링 기법을 통하여 고속화를 하고, 두 번째로는 GPGPU간의 P2P(peer-to-peer)데이터 전송을 이용한 스케쥴링을 했다. nVidia의 GTX680 2개 GPGPU를 이용하여 기존의 방법보다 약 50%의 속도 향상을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.213-214
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• 2017

홀로그램을 생성하기 위해서 많은 양의 계산을 필요하기 때문에 고속 홀로그램 생성 방법이 필요하다. 본 논문에서는 다중 프로세서와 다중 GPGPU의 스케줄링을 이용하여 고속화 하는 방법을 제안하고 구현하였다. 다중 프로세서를 이용하여 입력과 출력부분을 나누어 동기화 동작을 줄이고, 버퍼를 이용하여 커널과 커널 사이의 대기 시간을 줄일 수 있도록 스케줄링 하였다. nVidia사의 GTX680(Kepler구조) 2개를 이용하여 구현하였을 때, 이전 연구에서 제안한 방법에 비하여 약 70% 정도 계산시간을 줄일 수 있다.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.256-259
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• 2007

Multicast and Broadcast Service (MBS) provides flexible and efficient transmission of the same information to multiple users using shared radio resources on WiBro network. The advantage of this service is to achieve the most efficient use of radio and network resources as well as to lessen sender's processing load when sending the same information to multiple users. Though radio resources are saved since a multicast or broadcast transport connection is associated with a service flow, it is hard to change MBS service channel dynamically. In this paper, we propose a Radio Resource Management System (RRMS) for supporting dynamic scheduling of MBS service channels. Results show that our proposed scheme using Radio Resource Allocation Table (RRAT) can efficiently support MBS services by providing dynamic schedule for MBS service channels.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.380-383
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• 2020

본 작품은 코로나 바이러스로 인한 언택트 서비스의 부각과 더불어, 대중교통 이용시 승객들이 하차에 신경쓰지 않고 자신의 일에 집중 할 수 있도록 지원하기 위해 제작된 서비스이다. 버스 하차 전(혹은 승차 시) 미리 희망하는 하차 지점을 예약해놓으면 해당 정류장에 자동으로 버스의 하차벨을 울리게 된다. 스마트폰 앱과 버스에 설치된 단말을 활용하여 추가적인 설치비용을 절약하며, 이 후 완성된 시스템을 발전시켜 사용자별 타겟광고가 가능해지면 버스회사의 부족한 재원을 보다 확보할 수도 있다.

• Journal of KIISE:Databases
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• v.28 no.2
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• pp.243-252
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• 2001

이동 컴퓨팅 환경의 데이터 방송 시스템에서 클라이언트에게 최소의 응답시간을 제공할 수 있도록 방송을 스케쥴링 하는 것은 매우 중요하다. 본 논문에서는, 방송 스케쥴링 기법들의 성능을 응답시간 측면에서 모의 실험을 통하여 평가하고 분석한다. 기존 연구와는 달리, 클라이언트의 요구 형태 변화를 고려한 여러 가지 일반적이고 현실적인 응용 환경을 설정하여 평가한다.