• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.927-930
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• 2008

센서네트워크에서 센서노드는 제한된 에너지를 가지고 있다. 제한된 센서노드의 에너지를 절약하기 위한 여러 가지 연구가 진행되고 있으나, 센서노드의 에너지를 일정한 기간동안 유지하기 연구는 아직까지 미흡한 실정이다. 센서노드가 일정한 생존시간까지 에너지를 유지하기 위해서는 별도의 에너지 모델이 필요하다. 이를 위해 본 연구는 쿼리(응용)에 따른 센서노드의 에너지 소비를 5가지 상태로 나누고, 쿼리를 수행하기 위하여 각 상태별로 소비되는 에너지를 식별하여 센서노드가 생존시간까지 생존하기 위한 에너지모델을 제시하였다.

• The Journal of the Acoustical Society of Korea
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• v.15 no.2
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• pp.85-89
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• 1996

In this paper, transition constrained Hidden Markov Model(HMM) in which the transition between states occur only within prescribed time slot is proposed and the performance is evaluated in the noisy environment. The transition constrained HMM can explicitly limit the state durations and accurately de scribe the temporal structure of speech signal simply and efficiently. The transition constrained HMM is not only superior to the conventional HMM but also require much less computation time. In order to evaluate the performance of the transition constrained HMM, speaker independent isolated word recognition experiments were conducted using semi-continuous HMM with the noisy speech for 20, 10, 0 dB SNR. Experiment results show that the proposed method is robust to the environmental noise. The 81.08% and 75.36% word recognition rates for conventional HMM was increased by 7.31% and 10.35%, respectively, by using transition constrained HMM when two kinds of noises are added with 10dB SNR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.221-227
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• 2008

A vehicle routing problem with time constraint is one of the important problems in distribution and transportation. The service of a customer must start and finish within a given time interval. Our method is based on an improved operators of genetic algorithm and the objective is to minimize the cost of servicing the set of customers without being tardy or exceeding the capacity or travel time of the vehicles. This research shows that a proposed method based on the improved genetic search can obtain good solutions to vehicle routing problems with time constrained compared with a high degree of efficiency other heuristics. For the computational purpose, we developed a GUI-type computer program according to the proposed method and the computational results show that the proposed method is very effective on a set of standard test problems, and can be potentially useful in solving the vehicle routing problems.

• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.105-110
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• 2005

With the proliferation of multimedia group applications, the construction of multicast trees satisfying QoS requirements is becoming a problem of prime importance. In this paper, we study the delay- and delay variation-bounded multicast tree (DVBMT) problem which is NP-complete. The problem is to construct a spanning tree for destination node, which has the minimized multicast delay variation, and the delay on the path from the source to each destination is bounded. A solution to this problem is required to provide decent real-time communication services such as on-line games, shopping, and teleconferencing. Performance comparison shows that the proposed scheme outperforms DDVCA which is known to be effective so far in any network topology. The enhancement is up to about $3.6{\%}{\~}11.1{\%}$ in terms of normalized surcharge for DUVCA. The time complexity of our algorithm is $O(mn^2)$.

• The Journal of the Acoustical Society of Korea
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• v.24 no.5
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• pp.262-270
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• 2005

In this paper, a new temporal decomposition method is proposed. where not oniy distortion but also entropy are involved in segmentation. The interpolation functions and the target feature vectors are determined by a dynamic Programing technique. where both distortion and entropy are simultaneously minimized. The interpolation functions are built by using a training speech corpus. An iterative method. where segmentation and estimation are iteratively performed. finds the locally optimum Points in the sense of minimizing both distortion and entropy. Simulation results -3how that in terms of both distortion and entropy. the Proposed temporal decomposition method Produced superior results to the conventional split vector-quantization method which is widely employed in the current speech coding methods. According to the results from the subjective listening test, the Proposed method reveals superior Performance in terms of qualify. comparing to the Previous vector quantization method.

• KOREAN POULTRY JOURNAL
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• v.54 no.5
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• pp.212-213
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• 2022

• The Journal of the Korea Contents Association
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• v.14 no.7
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• pp.395-406
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• 2014

This research observes how an adolescent's usage of social network services is related with media use time, and also tries to verify how a parent's participation in acting to limit usage time serves as a mediating effect. For this analysis, data from The Korean Information Society Development Institute [Korea Media Panel Research] was used, being a survey conducted on 1,572 students from primary to secondary and high schools nationwide. The subjects' gender in the final analysis was 818 male students and 754 female students. In addition, primary school students consisted of 672 individuals, 416 were from secondary and 484 from high schools. To verify the appropriateness of the model proposed in this research, analyzed through the structural equation, using social network services(SNS) was not shown to have an effect on media usage time. However, there was an indirect effect from the use of alternative activities. In addition, the parent's limitation of usage showed no effect on media use time. This research attempts to identify the reasons why parents' limiting the usage time, along with alternative activities, do not have any significant effect in reducing media usage time in this era of smart media evolution. Further, this research hopes to suggest meaningful and political implications for the nation and society to understand and resolve media addiction.

• Journal of Internet Computing and Services
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• v.8 no.1
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• pp.25-31
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• 2007

The development of efficient Quality of Service (QoS) routing algorithms in high speed networks is very difficult since divergent services require various quality conditions, If the QoS parameter we concern is to measure the delay on that link, then the routing algorithm obtains the Least Delay (LD) path, Meanwhile, if the parameter is to measure of the link cast, then it calculates the Least Cost (LC) path. The Delay Constrained Least Cast (DCLC) path problem of the mixed issues on LD and LC has been shown to be NP-hard. The path cost of LD path is relatively mere expensive than that of LC path, and the path delay of LC path is relatively higher than that of LD path in DCLC problem. In this paper. we propose the algorithm based on estimated path for the DCLC problem and investigate its performance, It employs a new parameter which is probabilistic combination of cost and delay, We have performed empirical evaluation that compares our proposed algorithm with the DCUR in various network situations.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.66-68
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• 1998

실시간 데이터베이스 시스템에 있어서 동시성 제어는 제한시간을 달성하기 위한 중요한 요소중의 하나이다. 본 연구에서는 효율적인 실시간 데이터베이스 동시성 제어를 위한 알고리즘을 제안하다. 이 알고리즘은 실시간 데이터베이스에 적합한 낙관적 동시성 제어 기법(Optimistic Concurrency Control)을 근간으로 하며, 종료 트랜잭션의 여유시간(slack time)을 고려하여 좀더 많은 수행 트랜잭션의 마감시간 달성에 목표를 두었다.

• Digital Contents
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• no.10 s.77
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• pp.32-33
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• 1999

온라인 광고 시장이 인터넷 및 PC 통신의 성장과 함께 빠른 속도로 부상하고 있다. 온라인 광고는 일정시간 전달하는 일반 매체광고와는 달리 시간 제한 없이 상품의 정보를 전달할 수 있고 광고효과나 노출빈도도 바로 파악할 수 있는 장점이 있다. 지난해 국내 온라인 광고시장은 400억원에서 올해는 600억원으로 증가할 전망이다. 국내 온라인 광고 동향에 대해 살펴봤다.