• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권1호
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• pp.21-40
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• 2018

In this paper, we propose the distributed robust beamforming design scheme in cognitive two-way amplify-and-forward (AF) relay networks with imperfect channel state information (CSI). Assuming the CSI errors follow a complex Gaussian distribution, the objective of this paper is to design the robust beamformer which minimizes the total transmit power of the collaborative relays. This design will guarantee the outage probability of signal-to-interference-plus-noise ratio (SINR) beyond a target level at each secondary user (SU), and satisfies the outage probability of interference generated on the primary user (PU) above the predetermined maximum tolerable interference power. Due to the multiple CSI uncertainties in the two-way transmission, the probabilistic constrained optimization problem is intractable and difficult to obtain a closed-form solution. To deal with this, we reformulate the problem to the standard form through a series of matrix transformations. We then accomplish the problem by using the probabilistic approach based on two sorts of Bernstein-type inequalities and the worst-case approach based on S-Procedure. The simulation results indicate that the robust beamforming designs based on the probabilistic method and the worst-case method are both robust to the CSI errors. Meanwhile, the probabilistic method can provide higher feasibility rate and consumes less power.

• 한국세라믹학회지
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• 제38권1호
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• pp.100-105
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• 2001

An all solid-state thin film battery (TFB) was fabricated by growing, undoped and Pt-doped vanadium oxide cathode film ( $V_2$ $O_{5}$ ) on I $n_2$ $O_3$: Sn coated glass, respectively. Room temperature charge-discharge measurements based on Li/Lipon/ $V_2$ $O_{5}$ full-cell structure with a constant current clearly shows that the Pt-doped $V_2$ $O_{5}$ cathode film is superior, in terms of cyclibility. X-ray diffraction (XRD) results indicate that the Pt doping process induces a more random amorphous structure than an undoped $V_2$ $O_{5}$ film. In addition to its modified structure, the Pt-doped $V_2$ $O_{5}$ film has a smoother surface than the undoped sample. Compared to an undoped $V_2$ $O_{5}$ film, the Pt doped $V_2$ $O_{5}$ cathode film has a higher electron conductivity. We hypothesize that the addition of Pt alters electrochemical performance in a manner of making more random amorphous structure and gives an excess electron by replacing the $V^{+5}$. Possible mechanisms are discussed for the observed Pt doping effect on structural and electrochemical properties of vanadium oxide cathode films, which are grown on I $n_2$ $O_3$: Sn coated glass.

• 전자공학회논문지SC
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• 제44권1호
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• pp.1-11
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• 2007

본 논문에서는 UPS 인버터의 성능 개선을 위하여 출력측 LC 필터의 커패시터 전압과 전류의 2중 제어루프를 구성하고, 2중 제어루프에 디지털 제어시스템을 설계하였다. 또한, 디지털 제어기의 연산지연시간을 보상하기 위하여 이러한 연산지연시간을 인버터 플랜트의 고유한 파라미터로 가정하고, 플랜트 모델에 포함시켜 모델링 하였다. UPS 인버터 출력전압의 과도상태 응답특성을 개선하고, 파라미터 변동에 강인한 특성을 얻기 위하여 2중 제어루프에서 내부 전류 제어루프는 내부 모델 제어기를 제안하였다. UPS 인버터 출력전압의 0의 정상상태 오차를 얻기 위하여 외부 전압 제어루프는 비례 제어기와 공진 제어기를 병렬로 연결한 비례-공진 전압제어기를 제안하였다. 또한, 사용자에게 쉽게 UPS의 동작 상태를 표시하기 위하여 그래픽 사용자 인터페이스를 이용한 UPS의 모니터링 시스템을 구현하였다.

• 정보학연구
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• 제6권4호
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• pp.69-80
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• 2003

최근 전자상거래의 발전과 함께 소비자 피해도 급증하고 있다. 본 연구결과 전자상거래 피해 품목을 보면 정보통신 기기 및 서비스 위주에서 문화용품, 의류 생활용품으로 그 품목이 다변화되는 추세를 보이고 있었고 피해유형으로는 하프플라자의 피해 등으로 인하여 물품의 미인도 및 인도지연과 관련된 소비자 피해가 1,185.3%나 급증한 것으로 나타났다. 거래분야별로 보면 현재는 인터넷쇼핑몰과 관련된 피해가 90% 이상을 차지하고 있으나 향후 인터넷콘텐츠와 관련된 피해도 증가할 것으로 예측되었다. 인터넷콘텐츠의 경우 미성년자의 게임관련 피해가 가장 많은 사례로 나타났다. 그리고 피해가 다발하는 세부품목을 보면 디지털카메라, 노트북, 인터넷게임 등의 순으로 나타났다. 따라서 피해급증 분야에 대한 소비자보호 대책과 하프플라자와 같은 사기 피해에 대한 예방 대책 마련이 시급하며 장기적으로는 사업자의 의식개선을 통한 자율적인 소비자보호 체계구축이 필요한 것으로 나타났다.

• 전기학회논문지
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• 제57권2호
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• pp.276-285
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• 2008

These days the automobile industry, which has rapidly progressed, has been an indispensable part in social and economic activities as well as its research and development have been activated in response to various needs of consumers and markets. The second and third generation control system, getting count on safety and convenience differently than early circuits, cause the hypertrophy of wire harness. The J/Box(Junction Box), which distributes power and wires, was developed to solve the problem. As vehicles have been better in quantity and intelligence, however, environment-friendly electric apparatus system has continuously increased and ITS(Intelligent Transport System) has been introduced in earnest. In result, wires got complicated and multilateral and also there has been a stronger probability that vehicles are out of order due to various problems including mechanical failure. In this study, ISJB(Intelligent Smart Junction Box) was introduced to solve the problem. The diagnosis system was applied to prevent the overload and short of ISJE. Also, the state of vehicles displayed so that drivers monitor it in motion. Likewise error data are saved in the memory so that such data can be analyzed retrospectively. The busbar was adopted in to the main power terminal and the part of power pattern was coverd by lead. Because ISJB is more sensitive to heat in comparison to the busbar type J/Box. With regard the circuits related with safe, alternative circuits were set up in order that electronic devices may be normally operated even when an error arises. ISJB is expected to improve the safety and quality of vehicles.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1144-1153
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• 2015

The resonant mechanism of reradiation interference (RRI) over 1.7MHz from power transmission lines cannot be obtained from IEEE standards, which are based on researches of field intensity. Hence, the resonance is ignored in National Standards of protecting distance between UHV power lines and radio stations in China, which would result in an excessive redundancy of protecting distance. Therefore, based on the generalized resonance theory, we proposed the idea of applying model-based parameter estimation (MBPE) to estimate the generalized resonance frequency of electrically large scattering objects. We also deduced equation expressions of the generalized resonance frequency and its quality factor Q in a lossy open electromagnetic system, i.e. an antenna-transmission line system in this paper. Taking the frequency band studied by IEEE and the frequency band over 1.7 MHz as object, we established three models of the RRI from transmission lines, namely the simplified line model, the tower line model considering cross arms and the line-surface mixed model. With the models, we calculated the scattering field of sampling points with equal intervals using method of moments, and then inferred expressions of Padé rational function. After calculating the zero-pole points of the Padé rational function, we eventually got the estimation of the RRI’s generalized resonant frequency. Our case studies indicate that the proposed estimation method is effective for predicting the generalized resonant frequency of RRI in medium frequency (MF, 0.3~3 MHz) band over 1.7 MHz, which expands the frequency band studied by IEEE.

• 한국정보전자통신기술학회논문지
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• 제12권6호
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• pp.597-604
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• 2019

본 논문은 프로토콜 구현물이 프로토콜의 사양에 대한 적합성을 시험하기 위한 시험항목 생성시 CPP(중국 집배원 문제) 알고리즘의 개선된 적응적 적용 방법을 제안한다. 또한 본 논문에서 제안한 개선된 CPP 알고리즘 방법이 통신 프로토콜의 적합성 시험을 위한 시험항목 생성에 어떻게 적응될 수 있는지 B-ISDN Q.2931 호/연결 제어 절차에 실례로 적용하여 본다. 본 방법의 실험적인 적용 결과 기존의 시험열 생성 방법들에 비해 최적화된 최소 비용의 시험열을 생성함을 확인하였다. 본 논문의 제안된 방법은 표준화된 사양으로부터 최소 비용의 시험항목을 구하는 최적화 기법으로써의 장점을 가지고 있는데 본 논문의 개선된 CPP 알고리즘의 이 최적화 기법은 프로토콜 구현물의 적합성을 시험하기 위한 실재 환경에 실제적으로 적용될 수 있다. 향후 연구에서는 프로토콜 적합성시험을 위한 시험항목 생성시 상위 시험기와 하위 시험기간의 시험 조정 절차에서 발생할 수 있는 동기화 문제를 해결하고 적용하는 방안이 강구되어야 할 것으로 사료된다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권12호
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• pp.5107-5110
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• 2015

The State of Punjab has been in focus because of aperceived increasing rate of cancer. Both print and electronic media have created an impression that Punjab, especially the cotton belt of Malwa Region, has become a high incidence cancer region. Actually the increased number of cancer patients might be at least partly because of increasing population and heightened health awareness and reporting. The purpose of this study is to find out the pattern of cancer amongst patients registered in Mukh Mantri Punjab Cancer Rahat Kosh Scheme (MMPCRKS), under cancer registry at Rajindra Hospital Patiala from the various districts of Punjab. The study covers 500 cancer patients registered under MMPCRKS at Rajindra Hospital Patiala, for free cancer treatment. Information regarding age, gender, religion, method of diagnosis and affected sites was obtained. Results were analyzed statistically. Of the 500 patients, 65% were females and 35% were males. The most affected female age groups were 50-54 and 60-64; while males in the age groups of 65-69 and 60-64 had the highest risk. The leading cancers in females were breast followed by cervix and ovary where as in males they were were colon followed by esophagus and tongue. The commonest histological type was adenocarcinoma followed by squamous cell carcinoma. The increasing trend of cancer in Punjab is alarming. Since this study is a preliminary investigation, it could provide a leading role in prevention, treatment and future planning regarding cancer in Punjab.

• 대한기계학회논문집A
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• 제36권8호
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• pp.843-850
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• 2012

함정 전투체계의 운용개념 및 탐색 레이더의 운용성능을 고려하여 설계된 안테나는 반도체형 송수신기들로 구성된 능동배열안테나 시스템이다. 안테나 시스템을 구성하는 전자장비들을 배치하면, 전체 형상은 상당히 큰 크기의 박스 형태가 된다. 함정 마스트에 장착되어 기계적으로 회전하는 안테나 시스템은 가혹한 외부 환경으로부터 내부 장비를 보호하기 위해 밀폐된 하우징을 사용한다. 하우징의 외부형상을 결정할 때, 기존 설계는 강풍이 존재하더라도 정상 회전 유지가 중요한 설계 고려 요소이다. 최근에 함정의 생존성을 증대시키기 위해 저피탐 설계가 요구된다. 따라서 본 연구에서는 저피탐 설계요소를 추가하여 제안된 4 가지 모델에 대해서 외부 형상 설계를 분석하였다.

• 한국기계가공학회지
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• 제8권4호
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• pp.110-121
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• 2009

It is essential to embed product quality in the design process to win the global competition. Many components found in many products including automobiles and electronic devices are fabricated using sheet metal forming processes. Wrinkle and fracture are two types of defects frequently found in the sheet metal forming process. Reducing such defects is a hard problem as they are affected by many uncontrollable factors. Attempts to solve the problem based on traditional deterministic optimization theories are often led to failures. Furthermore, the wrinkle and fracture are conflicting defects in such a way that reducing one defect leads to increasing the other. Hence, it is a difficult task to reduce both of them at the same time. In this research, a new design method for reducing the rates of conflicting defects under uncontrollable factors is presented by using operating window and a sequential search procedure. A new SN ratio is proposed to overcome the problems of a traditional SN ratio used in the operating window technique. The method is applied to optimizing the robust design of a sheet metal forming process. To show the effectiveness of the proposed method, a comparison is made between the traditional and the proposed methods using simulation software, applied to a design of particular sheet metal forming process problem. The results show that the proposed method always gives a more robust design that is less sensitive to noises than the traditional method.