• The KIPS Transactions:PartD
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• v.12D no.1 s.97
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• pp.21-30
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• 2005

In mobile computing environments, a mobile host caches the data to use the narrow bandwidth efficiently and improve the response time. A server periodically broadcasts the update data for maintaining the cache consistency of a mobile host. However, a method for maintaining cache consistency using periodic invalidation report has a problem that defers the commit decision of a mobile transaction to guarantee its serializable execution. In this paper, we propose CCM-AD method that guarantees the serializable execution of a mobile transaction even in the case that it is executed using cached data. As CCM-AD method guarantees the serializable execution of mobile transactions by using the intersection between the data broadcast to mobile host and the data updated at server. Then the CCM-AD method can reduce the delay of commitment decision of a mobile transaction. Also our method can reduce the size of invalidation report.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.167-170
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• 2012

본 논문에서는 박자 분류 방법을 사용하여 다성 음악 신호의 템포 쌍을 검출하는 방법을 제안한다. 템포를 검출하는 방법은 음의 시작점을 추출하여 음악의 주기적인 흐름을 파악한 뒤, 그 주기를 템포로 변환하는 과정으로 구성된다. 제안한 기술은 템포로 추측되는 배수 관계의 템포 후보를 추출한 뒤, 템포 후보를 박자에 따라 분류하고 곡의 빠르기를 고려하여 최종 템포 쌍을 검출한다. 제안한 방법을 사용하여 높은 정확도로 템포 쌍이 검출되는 것을 확인하였다.

• 한국산학경영학회:학술대회논문집
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• 2006.12a
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• pp.93-105
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• 2006

본 연구의 중요한 실무적 시사점은 방송영상 분야에서 한국방송광고공사의 KODEX를 이용한 e-비즈니스의 추진이 기업의 업무처리 비용을 감소시켜주고, 업무 추진에 따른 위험을 감소시켜주며, 또한 업무 효율성을 높여주어 경영성과 개선에 기여를 한다는 것을 보여준다. 즉, 본 사례연구 결과는 방송광고산업 분야에서의 e-비즈니스들에게 경영성과를 개선 기회를 제공해 주기 때문에 방송광고산업 분야의 기업들에게 성공적인 e-비즈니스 추진에 가이드라인을 제시해준다는데 있다.

• Journal of Korea Multimedia Society
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• v.11 no.3
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• pp.398-403
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• 2008

Data broadcasting is a mechanism to transmit information to clients in simplex transmission environments. In this mechanism, server transmits to repeat all information to all users and users use a necessary data when the data is transmitted. Therefore users are waiting the necessary data until the data is transmitted. It is important to reduce user's waiting time. Server schedules the data to reduce waiting time. In this paper, we study efficient data scheduling algorithm. The result shows that the performance of the proposed method is increased 13 percent compared to the method considering only request frequency.

• Journal of Broadcast Engineering
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• v.8 no.2
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• pp.109-115
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• 2003

In this paper we propose an efficient method to broadcast digital television signals using Single Frequency Networks (SFNs) in the Advanced Television Systems Committee (ATSC) transmission systems. Since the proposed schemes to synchronize multiple transmitters minimize the changes from the conventional ATSC system, the hardware complexity for the changes is very low. Our simulation results show that the proposed scheme makes less than 0.1 dB degradation at the threshold of visibility (TOV： BER= 3$\times$$10^{-6}$) in the additive white Gaussian noise (AWGN) channel. It is possible to reduce the performance degradation by increasing an initialization period of the proposed scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.33-38
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• 2010

This paper examines the feasibility of using periodically varying dielectric layers with dielectric constant ${\epsilon}_1$ and ${\epsilon}_2$ at millimeter wave frequency for implementing the frequency-selective reflectors that permit feed separation in large aperture reflecting antenna systems. For oblique incidence, it is found that the total reflection can be obtained at different frequencies for proper choices of ${\epsilon}_1$, ${\epsilon}_2$ and the geometric parameters. In the frequency-selective reflector designed, the bandwidth for 90% reflection is always found to be much narrower than that for 90% transmission.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.247-252
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• 2019

The diffraction properties of optical signals by multi-layered periodic structures is formulated in two-dimensional space by using Fourier expansions associated with basic grating profile. The fields in each layer are then expressed in terms of characteristic modes, and the complete solution is found rigorously by using a modal transmission-line theory(MTLT) to address the pertinent boundary-value problems. Such an approach can treat periodic arbitrary gratings containing arbitrarily shaped dielectric components, which may generally have optical properties along directions that are parallel or perpendicular to the multi-layers. This paper illustrates the present approach by comparing our numerical results with data reported in the past for simple periodic circular 2D structures. In addition, this proposed theory can apply easily for more complex configurations, which include multiple periodic regions with several possible canonic shapes and high dielectric constants.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.344-345
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• 2011

본 논문에서는 모니터 상단의 일반 웹 카메라를 이용하여 사용자의 올바른 자세와 올바르지 않은 자세를 추정하고 사용자가 스스로 교정을 유도할 수 있는 새로운 개념의 어플리케이션을 소개한다. 교정의자나 허리 보호대 등의 도구가 없이 카메라 하나로 사용자가 자기 자세에 대한 인식을 할 수 있도록 제안하는 시스템이다. 정면 시점에서 바라보는 사용자의 자세는 얼굴과 어깨의 특징으로 판단하고, 초기화한 올바른 자세와 비교하여 사용자에게 경고 알림을 해주는 과정으로 진행된다. 주기적으로 자세를 확인하는 시스템을 통하여 사용자가 컴퓨터를 하는 자세에 대해 자각시킴으로써 올바른 자세를 가지도록 유도할 수 있음을 확인하였다.

• The KIPS Transactions:PartD
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• v.10D no.6
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• pp.961-970
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• 2003

In data broadcasting environments, the server periodically broadcasts data items in the broadcast channel. When each client wants to access any data item, it should monitor the broadcast channel and wait for the desired item to arrive. Client data caching is a very effective technique for reducing the time spent waiting for the desired item to be broadcastted. This paper proposes a new client cache management scheme, named LRU-CFP, to reduce this waiting time ans evaluates its performance on the basis of a simulation model. The performance results indicate that LRU-CFP scheme shows superior performance over LRU, GRAY and CF in the average response time.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.339-349
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• 2005

For recent years, data broadcast technology has been recognized as a very effective data delivery mechanism in mobile computing environment with a large number of cli;ents. Especially, a hybrid broadcast algorithm in real-time environment, which integrates one-way broadcast and on-demand broadcast, has an advantage of adapting the requests of clients to a limited up-link bandwidth and following the change of data access pattern. However, previous hybrid broadcasting algorithms has a problem in the methods to get a grip on the change of data access Pattern. It is caused by the diminution of requests for the data items which are contained in periodic broadcasting schedule because they are already broadcasted. To solve this problem, existing researches may remove data items in periodic broadcasting schedule over a few cycles multiplying cooling factor or find out the requests of data items with extracting them on purpose. Both of them are the artificial methods not considering the property of data. In this paper, we propose a real-time adaptive hybrid broadcasting based on data type(RTAHB-DT) to broadcast considering data property and analysis the performance of our aigorithm through simulation study.