• Journal of Communications and Networks
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• 제18권3호
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• pp.476-483
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• 2016

Super Wi-Fi is a Wi-Fi-like service exploiting TV white space (WS) which is expected to achieve larger coverage than today's Wi-Fi thanks to its superior propagation characteristics. Super Wi-Fi has been materialized as an international standard, IEEE 802.11af, targeting indoor and outdoor applications, and is undergoing worldwide field tests. This paper demonstrates the true potential of indoor Super Wi-Fi, by experimentally comparing the signal propagation characteristics of Super Wi-Fi and Wi-Fi in the same indoor environment. Specifically, we measured the wall and floor attenuation factors and the path-loss distribution at 770MHz, 2.401 GHz, and 5.540 GHz, and predicted the downlink capacity of Wi-Fi and Super Wi-Fi. The experimental results have revealed that TVWS signals can penetrate up to two floors above and below, whereas Wi-Fi signals experience significant path loss even through a single floor. It has been also shown that Super Wi-Fi mitigates shaded regions of Wi-Fi by providing almost-homogeneous data rates within its coverage, performs comparable to Wi-Fi utilizing less bandwidth, and always achieves better spectral efficiency than Wi-Fi. The observed phenomena imply that Super Wi-Fi is suitable for indoor applications and has the potential of extending horizontal and vertical coverage of today's Wi-Fi.

• Journal of Genetic Medicine
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• 제13권2호
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• pp.59-64
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• 2016

Gaucher disease type 1 (GD1) is an inherited lysosomal storage disorder caused by deficiency of acid ${\beta}$-glucosidase. The diminished enzyme activity leads to the accumulation of substrates and results in multi-systemic manifestations including hepatosplenomegaly, anemia, thrombocytopenia, and bone diseases. Enzyme replacement therapy (ERT) by infusion of recombinant protein has been the standard treatment for over 20 years. Despite the successful long-term treatment with ERT, several unmet needs remain in the treatment of GD1 such as severe pulmonary and skeletal manifestations. Substrate reduction therapy (SRT) reduces the accumulation of substrates by inhibiting their biosynthesis. Eliglustat, a new oral SRT, was approved in United States and Europe as a first-line therapy for treating adult patients with GD1 who have compatible CYP2D6 metabolism phenotypes. Although eliglustat is not yet available in Korea, introduction and summary of this new treatment modality are provided in this paper by review of literatures. Despite the fact that there are only limited studies to draw resolute conclusions, the current data demonstrated that eliglustat is not inferior to ERT in terms of its clinical efficacy. The approval of eligustat enables eligible adult GD1 patients to have the option of oral therapy although it still needs further studies on long-term outcomes. The individual patient should be assessed carefully for the choice of treatment modality when eliglustat becomes available in Korea. Furthermore, the clinical guidelines for Korean patients with GD1 regarding the use of eliglustat needs to be developed in near future.

• 한국실내디자인학회논문집
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• 제21권3호
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• pp.31-39
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• 2012

This is the time we need differentiated strategy due to consumer's standard of purchasing is becoming more complicated and corporate marketing war is intensely competitive. For a long-term strategy, making competitive corporate image is important because companies have their own competitiveness. In addition, importance of having a relationship with customer is magnified through consumers'direct and indirect experience. "The corporate complex cultural space is designed place for experiential marketing to convey its meaning to consumers." Under above concept, this study analyzed the theory of experiential marketing and conducted a survey which is based on experiential marketing strategic module (SEMs) using the analyzed theory. This study drew expression characteristics of space through case analysis and conducted a survey to have more effective corporate complex cultural space. As a result, the experience in the space enables people to understand of the space through five senses, not consist of simply chucks of sense-date, and this result emphasizes the importance of 'Event' because people tend to escape from restriction for reality to relive stress and have emotional satisfaction. In addition, it shows expression characteristics which provide sympathy as a flexible interaction through symbolical image. The result of the expression characteristics' survey is showed up to improve effect of corporate complex cultural space. This study is analyzing the corporate complex cultural space through experience marketing for the company which wants provide differentiated experience of various space expression methods and catching current position. Also, this study places its significance to give a way to increase space preference and effect of corporate complex cultural space. Based on the result of this study, I hope the future corporate complex cultural space will develop refreshingly.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.179-190
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• 2010

This paper describes a new stochastic heuristic algorithm in engineering problem optimization especially in power system applications. An improved particle swarm optimization (PSO) called adaptive particle swarm optimization (APSO), mixed with simulated annealing (SA), is introduced and referred to as APSO-SA. This algorithm uses a novel PSO algorithm (APSO) to increase the convergence rate and incorporate the ability of SA to avoid being trapped in a local optimum. The APSO-SA algorithm efficiency is verified using some benchmark functions. This paper presents the application of APSO-SA to find the optimal location, type and size of flexible AC transmission system devices. Two types of FACTS devices, the thyristor controlled series capacitor (TCSC) and the static VAR compensator (SVC), are considered. The main objectives of the presented method are increasing the voltage stability index and over load factor, decreasing the cost of investment and total real power losses in the power system. In this regard, two cases are considered: single-type devices (same type of FACTS devices) and multi-type devices (combination of TCSC, SVC). Using the proposed method, the locations, type and sizes of FACTS devices are obtained to reach the optimal objective function. The APSO-SA is used to solve the above non.linear programming optimization problem for better accuracy and fast convergence and its results are compared with results of conventional PSO. The presented method expands the search space, improves performance and accelerates to the speed convergence, in comparison with the conventional PSO algorithm. The optimization results are compared with the standard PSO method. This comparison confirms the efficiency and validity of the proposed method. The proposed approach is examined and tested on IEEE 14 bus systems by MATLAB software. Numerical results demonstrate that the APSO-SA is fast and has a much lower computational cost.

• Industrial Engineering and Management Systems
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• 제11권3호
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• pp.233-240
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• 2012

The implementation of business process management (BPM) systems in large number of business organizations transforms BPM system into such a level of maturity and tends to collect large repositories of business process (BP) models. This issue encourages BP flexibility that leads to a large number of process variants derived from the same model, but differing in structure, to be stored in the large repositories of BP models. Therefore, the repositories may include thousands of activities and related business objects with variation of requirements and quality of service. It is a common practice to customize processes from reference processes or templates in order to reduce the time and effort required to design and deploy processes on all levels. In order to address redundancy and underutilization problems, a generic process model, called as reference BP, is absolutely necessary to cover the best of process variants. This study aims to develop multiple-objective business process genetic algorithm (MOBPGA) to find a set of non-dominated (Pareto) solutions of business reference model to enhance conventional approach which considered only a single objective on creating BP reference model by using proximity score measurement. A mixed-integer linear program is constructed to evaluate performance of the proposed MOBPGA on small-scale problems by using standard measures for multiple-objective techniques. The results will show the viability of applying MOBPGA in terms of simultaneously maximizing proximity score measurement, minimizing total duration, and total costs of the selected reference model.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 추계종합학술대회
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• pp.224-229
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• 1999

음성 인식 연구는 유사음소 단위의 인식시스템을 구축하는 방향과 단어 단위의 인식시스템에서의 효율을 최대화하는 방향으로 이루어지고 있다. 이중 유용한 유사음소 단위의 인식시스템 구현을 위해서는 음소의 경계 검출 문제와 검출된 음소에 대한 인식률 향상 문제가 해결되어야 한다. 기존의 LPC(Linear Predictive Coefficient) 방법들은 기준 음소데이터의 LPC와 입력 음성프레임의 LPC 사이의 거리를 Itakura-Saito 방법으로 구하여 음소의 경계를 검출하였으며, 근래에는 MFCC(Mel-Frequency-Cepstrum Coefficient)를 이용하여 스펙트럼의 천이부분을 음소의 경계로 검출하는 방법들이 제안되어왔으나 이러한 방법들은 공통적으로 적응성이 미비하다는 단점이 있다. 본 논문에서는 이러한 단점을 극복하기 위해 음소경계검출을 위해서는 auto-correlation을 이용하고 음소인식을 위해서는 적응성이 뛰어난 다층 Feed-Forward 신경망을 사용하는 새로운 인식시스템을 제안하였다 제안하는 시스템은 기존의 방법들보다 적응성이 뛰어나고 특징추출부분과 인식 부분의 알고리듬이 독립적이라는 장점을 가지며 프레임단위의 음소인식시스템의 구현 가능성을 확인해 주었다.

• 한국정보통신학회논문지
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• 제15권5호
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• pp.1155-1163
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• 2011

본 논문에서는 깊이 맵(depth map)에 대한 효율적인 부호화를 위하여 전처리 기법을 제안한다. 현재 3차원 비디오 부호화(3D video coding : 3DVC)에 대한 표준화가 진행 중에 있지만 아직 깊이 맵의 부호화 방법에 대한 표준은 확정되지 않은 상태이다. 제안하는 기법에서는 먼저 입력된 깊이 맵의 히스토그램 분포를 가우시안 혼합모델(Gaussian mixture model : GMM) 기반의 EM(expectation maximization) 군집화 기법을 이용하여 분리한다. 분리된 히스토그램을 기반으로 깊이 맵을 여러 개의 레이어로 분리하게 된다. 분리된 각각의 레이어에서 배경과 객체의 포함여부에 따라 다른 조건의 민쉬프트 필터(mean shift filter)를 적용한다. 결과적으로 영상내의 각 영역 경계는 최대한 살리면서 영역내의 화소 값에 대해서는 평균 연산을 취하여 부호화시 효율을 극대화 하고자 하였다. 다양한 실험영상에 대하여 제안한 기법을 적용한 깊이 맵을 부호화하여 비트율(bit rate)이 감소하고 부호화 시간도 다소 줄어드는 것을 확인 할 수 있었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.359-364
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• 2006

Interference can seriously degrade the performance of GPS receiver because GPS signal has extremely low power at earth surface. This paper presents a Narrowband Interference Excision Filter (NIEF) in frequency domain that removes narrowband interferences with small signal loss. A NIEF transforms the received GPS signals with interferences into the frequency domain with FFT and then compute statistics such as mean and standard deviation to determine an excision threshold. All spectrums exceeding the threshold are removed and the remaining spectrums are restored by IFFT. A NIEF effectively can remove various and strong interferences with a simple structure. However, the signal power loss is unavoidable during FFT and IFFT. Besides the hamming window and overlap technique, a threshold-whitening technique and an adaptive detection threshold are adopted to effectively reduce the signal power loss. The performance of implemented NIEF is evaluated using real signals obtained by 12 bit GPS signal acquisition board. The output of NIEF is fed into the Software Defined Receiver to evaluate the acquisition and tracking performance. Experimental results shows that many types of interference such as single-tone CWI, AM, FM, swept CWI and multi-tones CWI are effectively mitigated with small signal power loss.

• 한국산학기술학회논문지
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• 제5권4호
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• pp.309-314
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• 2004

네일 파일(nail file)을 제조할 때 재료는 강판(두께 0.5㎜)을 사용하고 가공방법은 외형형상을 만들고 Φ 0.8-Φ 1.0㎜의 구멍을 약 300여개 뚫어 완성한다. 이들의 가공방법은 에칭(etching)에 의존하여 제조원가의 33%를 에칭비가 차지하고 있으므로 제조원가의 상승원인이 되고 에칭시 부식제(etching reagent)의 잔류도 환경 친화적이 못되며 재료가 강판이기 때문에 제품에 녹(rust)이 생기므로 이들의 문제점을 해결하고자 다음과 같이 연구개발을 수행하였다. 제품의 녹 방지를 할수 있는 적합한 재질 선택 방법을 고찰하고, 에칭 가공방법을 사용하지 않고 금형을 이용한 프레스 가공으로 교체하기 위하여 프레스 스탬핑시의 스트립 레이아웃(strip layout)기법을 연구개발하고, 금형 부품 중에서 작업 중 절손이 빈번한 보통의 표준펀치를 퀼형의 펀치로 개발 하므로써 프로그레시브 퍼퍼레이팅 금형(progressive perforating die)을 개발하게 되었다.

• 정보처리학회논문지A
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• 제17A권2호
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• pp.81-92
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• 2010

진동 정보를 통해 기계 설비의 상태나 고장 유무를 판단하는 연구들이 다수 진행 중에 있는데, 대부분의 연구에서는 설비에 대한 진동을 모니터링하거나 고장 유무를 판별하여 사용자에게 알리는 수준이다. 본 논문에서는 진동에 의한 고장 진단과 판별을 보다 정교하게 수행하는 선박 엔진의 고장 감지 기법과 시스템을 제안하였다. 일차적으로 이중적 진동 정보 판별 기법을 적용하여 진동 정보를 확인한 다음에 고장 유무를 검사한다. 만일 고장이 발생한 경우에는 진동 정보의 오류 부분만을 이용하여 고장 진동 파형에 대한 오차 범위를 기준으로 어떤 유형의 고장인지를 판별할 수 있는 기법을 적용하였다. 또한 선박의 진동 경향 분석과 엔진 안전 보존을 목적으로 진동 정보를 데이터베이스에 저장하고 추적할 수 있도록 시스템을 구현하였다. 제안 시스템을 선박 엔진의 고장 판별 유무와 고장 진동 파형 감별 인자에 대해 실험을 수행한 결과 고장 유무 판별은 약 100% 정확성을 가졌고 고장 진동 파형의 유형 인식에서는 약 96% 정확성을 가졌다.