• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.103-109
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• 2014

This paper related with the CR-MMA which is possible to improving the equalization performance by applying the concept of constellation reduction in the MMA adaptive equalization alogorithm in order to reduce the intersymbol interference that is occurred in the nonlinear communication channel. In the updating process of MMA adaptive equalizer, the error signal is being obtained by using the equalizer output, and the performance will be degraded by the increase the error signal in the high order QAM constellation. But by using the constellation reduction, the high order QAM signal will be changed to the 4-QAM signal constellation and then the error signal will be obtained. By doing so, the error signal will be minimized and it is possible to improve the equalization performance in the high order QAM transmitted signal. The Computer simulation was performed in order to compare the performance of the proposed CR-MMA algorithm and original MMA algorithm in the same communication channel and noise environment. For this, the recoverd signal constellation which is the output of equalizer, residual isi and MD (Maximum Distortion) learning curve which is represents the convergence performance and SER which is represents the roburstness of noise were used. As a result of simulation, the CR-MMA has more superior to the MMA. And it was confirmed that the CR-MMA has roburstness to the noise in the SER performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.113-120
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• 2005

3D reconstruction of a scene structure from un-calibrated image sequences has been long one of the central problems in computer vision. For 3D reconstruction in Euclidean space, projective reconstruction, which is classified into the merging method and the factorization, is needed as a preceding step. By calculating all camera projection matrices and structures at the same time, the factorization method suffers less from dia and error accumulation than the merging. However, the factorization is hard to analyze precisely long sequences because it is based on the assumption that all correspondences must remain in all views from the first frame to the last. This paper presents a new projective reconstruction method for recovery of 3D structure over long sequences. We break a full sequence into sub-sequences based on a quantitative measure considering the number of matching points between frames, the homography error, and the distribution of matching points on the frame. All of the projective reconstructions of sub-sequences are registered into the same coordinate frame for a complete description of the scene. no experimental results showed that the proposed method can recover more precise 3D structure than the merging method.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.96-107
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• 1999

The generalized sidelobe cancellers(GSC's) ar used for suppressing an interference in array radar. The frequency-domain GSC's have a faster convergence rate than the time-domain GSC's because they remove the correlation between the interferences using a frequency-domain least mean square(LMS) algorithm. However, we have not fully used the advantage of the frequency-domain GSC's since we have always updated the weights of all frequency bins, even the interferer free frequency bin. In this paper, we propose a new frequency-domain GSC based on constant false-alarm rate(CFAR) detector, of which GSC adaptively determine the bin whose weight is updated according to the power of each frequency bin. This canceller updates the weight of only updated according to the power of each frequency bin. This canceller updates the weight of only the bin of which the power is high because of the interference signal. The computer simulation shows that the new GSC reduces the iteration number for convergence over the conventional GSC's by more than 100 iterations. The signal-to-noise ration(SNR) improvement is more than 5 dB. Moreover, the number of renewal weights required for the adaptation is much fewer than that of the conventional one.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1409-1417
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• 2020

The purpose is to increase the likelihood of physical education students for employment in public institutions by examining the priority for hiring sports-related public institutions. The subject of the study was purposeful sampling of a total of 11 persons including 4 sports professors, 3 NCS experts in sports field, 2 judges from public sports institutions, and 2 personnel in charge of hiring public institutions. Through this process, from January 3 to March 12, 2020, the importance of priority was analyzed using hierarchical structure analysis using the main factors of NCS vocational basic competency. All data are coded so that statistical processing can be performed. Using SPSS/PC (ver. 21.0) for Windows, the hierarchical structure analysis was used for frequency analysis and priority determination. First, communication skills (.231), organizational comprehension skills (.177), resource management skills (.128), interpersonal skills (.110), vocational ethics (.082), problems in the major areas of recruitment of sports-related public institutions Solving ability (.061), information ability (.056), mathematical ability (.054), self-development ability (.052), and description ability (.049) were analyzed in order. Second, in terms of evaluation items, communication is communication skills (.442), mathematical skills are basic computation skills (.512), problem solving skills are thinking skills (.722), self-development skills are self-management skills (.587), Resource management ability was analyzed in order of time management ability (.531), interpersonal relationship ability as teamwork ability (.382), information ability in computer use ability (.677), technical ability in technology understanding ability (.599).

• Journal of Korean Library and Information Science Society
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• v.29
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• pp.443-464
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• 1998

21세기를 맞이하여 대학도서관은 정보기술의 도입, 업무내용의 변화, 이용자의 요구변화등 급격하게 변화하는 새로운 환경에 직면해 있다. 본 연구는 한국의 대학도서관 조직구조의 현황에 대한 분석과 함께 다양한 조직이론들과 정보환경의 변화에 기초해서 도서관조직을 활성화시키기위한 개념적인 조직모델을 제시하고자 한다. 한국의 대학도서관은 거의 10년동안 법적인 제약과 조직내외의 환경적인 한계 등으로 인해 전산화시스템의 도입, 도서관부관장의 임명, 그리고 도서관과 컴퓨터 센터와의 통합시도와 같은 약간의 변화외에는 거의 변화가 없었다. 전형적인 한국의 대학도서관은 수서, 기술서비스, 열람과 참고봉사 부문으로 조직되었다. 여기서 수서 기능을 기술서비스의 부문으로 간주한다면, 본 연구의 대상인 대학도서관 114개관 중 95개관(82.5%)이 전통적인 도서관조직의 형태인 기술서비스와 공공서비스 부문으로 조직된 것으로 나타났다. 본 연구에서는 전통적인 도서관조직의 문제점들을 급복할 수 있는 21세기의 개념적인 대학도서관 조직모델로서, 네가지 부문 - 서비스 부문, 서비스지원 부문, 기술지원 부문, 그리고 통합·조정부문-을 대학도서관의 개념적인 기본 구성요소로써 제안하였다. 그러나 모든 도서관의 서비스나 업무과정에 대해 적합한 잉상적인 조직구조는 없으며, 조직의 재조직과정은 도서관의 형태와 목적, 업무과정에 따라 매우 다양하다. 따라서 도서관의 재조직화는 환경의 변화에 따라 끊임없는 과정이 될 것이며, 도서관조직의 성공은 이러한 변화에 적응할 수 있는 개인과 조직의 역량에 달려있다고 하겠다.대한 순서에 있어서 차이가 있다. 4) 도서관에 대한 태도에 있어서 두 집단은 상이한 입장을 보이고 있다. 학자들의 과반수는 중요 정보원으로서 자신의 개인장서를 활용하며, 도서관의 장서 및 그 조직방법에 대해서도 별로 만족하지를 못하고 있다. 반면에, 실무가들은 도서관에 대하여 비교적 만족하며 따라서 도서관에 대한 이용도도 높다. 5) 두 집단 모두 보조인을 적극적으로 활용하지 않으며 사서의 도움을 받는 경우도 극소수에 불과하다. 이러한 조사결과를 기초로 하여 볼 때 법률전문직을 둘러싼 정보환경을 개선하기 위하여는, 인쇄된 일차적 정보자료의 검색방법등을 개선하고, 나아가서는 법령과 판례정보를 위한 효율적인 시스템을 구축하며, 뿐만 아니라 이용자의 요구에 충분히 대처할 수 잇는 도서관으로 변화되는 것이다. 이와 함께 가장 중요한 것은 법과대학과 사법연수원에서 법학 연구방법에 관한 강좌를 개설하여 각종 법률정보원의 활용 내지 도서관 이용방법에 관하여 교육하는 것이다.글을 연구하고, 그 결과에 의존하여서 우리의 실제의 생활에 사용하는 $\boxDr$한국어사전$\boxUl$등을 만드는 과정에서, 어떤 의미에서 실험되었다고 말할 수가 있는 언어과학의 연구의 결과에 의존하여서 수행되는 철학적인 작업이다. 여기에서는 하나의 철학적인 연구의 시작으로 받아들여지는 이 의미분석의 문제를 반성하여 본다. 것이 필요하다고 사료된다.크기에 의존하며, 또한 이러한 영향은 $(Ti_{1-x}AI_{x})N$ 피막에 존재하는 AI의 함량이 높고, 초기에

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1503-1514
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• 2006

Today, consumers can access Internet from everywhere, therefore most commercial and other organizations provide their services on the Web. As the result, countless Web service systems are already on the Internet and more systems are under construction. Therefore, many researches of verifying that the system to be constructed will not have any deadlock and will run successfully without any problem at the early stage of design have been performed. Several Petri net based verification methods have also been published. However, they have focused on building Petri net models of Web service systems and none of them introduces efficient analysis methods. As a mathematical technique with which we can find the minimum duration time needed to fire all the transitions at least once and coming back to the initial marking in a timed net, the minimum cycle time method has been widely used in computer system analysis. A timed net is a modified version of a Petri net where a transition is associated with a delay time. A delay time used in a timed net is a constant even though the duration time associated with an event in the real world is a stochastic number in general. Therefore, this paper proposes 'Mixedly Distributed Stochastic Timed Net' where a transition can be associated with a stochastic number and introduce a minimum cycle time analysis method for 'Mixedly Distributed Stochastic Timed Net'. We also introduce a method of analysing a Web service system's response time with the minimum cycle time analysis method for 'Mixedly Distributed Stochastic Timed Net.'.

• The KIPS Transactions:PartC
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• v.11C no.3
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• pp.395-400
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• 2004

Being aware of growing needs for wireless communication led to the development of UWB systems, this study proposed an impulse for single band UWB systems which does not count a carrier; analyzed the characteristics and the problems of pulses suggested by the existing poise of the Un system; finally, proposed TDMG(Time Delay Multiple Gaussian) pulse that generates signals of UWB without attenuation of pulse width. The hardware structure of the TDMC pulse for the single band UWB system was modelled after describing the pulse in a mathematical method in an attempt to compare with performances of the existing pulses through computer simulation. The outcome of the test unveiled the fact that each center frequency of the TDMG pulse rose approximately 1GHz, and also each l0dB fractional bandwidth of the TDMG pulse was widened over 1GHz. In the case of derivative, center frequencies of the TDMG pulse rose over 1GHz each. As a consequence, the TDMG pulse appeared to have better quality frequency, satisfying the characteristics of spectrum and the band of frequency recommended by the FCC and decreasing interference with other wireless communication systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.449-455
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• 2006

Due to advance in multimedia applications and integrated Internet services, the optical access networks have been actively studied. In particular, Ethernet passive optical network (EPON) has received much attention due to high bandwidth provision with low cost. In EPON system, the data transmission is carried out in two directions: downstream (from OLT to ONU) and upstream (from ONU to OLT). The downstream data is broadcasted to every ONUs, while the upstream data is point-to-point transmitted between each ONU and OLT, where the uplink is shared by all ONUs in the form of TDMA. The bandwidth allocation algorithm is required to efficiently manage the bandwidth on the uplink. The limited algorithm was proposed to enhance the capability of dynamic bandwidth allocation. In this paper, we propose the adaptive limited algorithm to enhance the shortcomings of limited algorithm. The adaptive limited algorithm enhances the dynamics on bandwidth allocation, and at the same time controls the fairness on packet delay. Through the computer simulations, it is shown that the adaptive limited algorithm achieves high dynamic on bandwidth allocation, maintains a good fairness on packet delay between ONUs, and keeps the fairness on the bandwidth on the demand basis.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.11_12
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• pp.541-556
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• 2005

The memory access latency of the system has been a primary factor of performance degradation in single-processor system and multi-processor system. The remote memory access latency takes a lot of overhead over the local memory access latency especially in the distributed shared-memory system. To resolve this problem, the multi-level cache architecture that contains a remote cache in the multi-processor system has been proposed. In this paper, we propose a new cache replacement policy that improves the performance of the multi-processor system with the remote cache. If the multi-level cache keeps the multi-level inclusion(MLI) property and uses the LRU(Least Recently Used) cache replacement policy, the LRU information of the higher-level cache(a processor cache) would be different with that of the lower-level cache(a remote cache). In this situation, the replacement of a remote cache line can induce the exchange of a processor cache line that is used by the processor. It is a main factor of performance degradation in a whole system. To alleviate this disadvantage of the LRU replacement polity, the new policy analyses tht processor's remote memory access pattern of each node and uses this information to reduce the number of invalidations of the useful cache line in the higher-level cache. The new replacement policy of the remote cache can improve the performance by $3.5\%$ in maximum and $2.5\%$ in average on SPLASH-2 benchmarks, compared to the general LRU cache replacement policy.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.4
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• pp.135-140
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• 2015

The WDSS improves defensive capacity against web application layer DDoS attack by using web cache server and L7 switch which are added on the DDoS shelter system. When web DDoS attack occurs, security agents divert traffic from backbone network to sub-network of the WDSS and then DDoS protection device and L7 switch block abnormal packets. In the meantime, web cache server responds only to requests of normal clients and maintains stable web service. In this way, the WDSS can counteract the web DDoS attack which generates small traffic and depletes server-client session resource. Furthermore, the WDSS does not require IP tunneling because it is not necessary to retransfer the normal requests to original web server. In this paper, we validate operation of the WDSS and verify defensive capability against web application layer DDoS attacks. In order to do this, we built the WDSS on backbone network of an ISP. And we performed web DDoS tests by using a testing system that consists of zombie PCs. The tests were performed by three types and various amounts of web DDoS attacks. Test results suggest that the WDSS can detect small traffic of the web DDoS attacks which do not have repeat flow whereas the formal DDoS shelter system cannot.