• 전력전자학회논문지
• /
• 제7권3호
• /
• pp.237-243
• /
• 2002

단상 위상각제어시스템의 경우 제어기의 구조상의 단순함과 저가격화로 인해 많은 노이즈가 발생함에도 불구하고 트라이액 교류 위상각제어기를 속도제어기로 사용하고 있다. 시판되는 진공청소기의 경우 트라이액의 위상각을 조절하여 속도를 제어하고 있는데 고조파전류의 발생을 최소화로 하기 위해서 속도의 선형성을 고려하지는 않고 제작하고 있는 경우가 대부분이다. 본 논문에서는 진공청소기용 위상각 제어기에 파라미터 추정에 의한 실제작 시스템으로 고조파가 많이 발생되는 특정 트라이액 트리거 위상각에서도 고조파전류가 효과적으로 감소되고 부수적으로 지연각이 없어지는 고조파전류 감쇠용 위상제어기의 설계 및 제작하여 실험을 통해 입증하였다.

• 한국의류산업학회지
• /
• 제7권6호
• /
• pp.594-600
• /
• 2005

This study investigated adolescents' shopping orientation and price perception according to socio statistics and their experience of internet shopping mall. We distributed the questionnaire to 411 high school students in near Seoul. In the order of high shopping orientation, they showed 'compare products', 'enjoy as leisure', 'shop loyalty', 'discount shopping', and 'brand shopping' orientation. In the order of high price perception, they showed 'economic', 'value', 'brand-quality', and 'price knowledge'. The higher in 'shop loyalty', 'enjoy as leisure' in the shopping orientation, the higher in the price concept of 'price knowledge'. Adolescents who have experience to shopping through internet shopping mall, have the higher enjoy as leisure, shop loyalty, compare products' in shopping orientation, and the higher 'economic, price knowledge' in price perception than those who have not. Socio-statistics parameters are found to affect adolescents' shopping orientation and price perception. Adolescents had average scores in 'shop loyalty', while they had high scores in 'compare products'. Thus, in order to have superior position in adolescent's market, detailed product specification and information are necessary to enhance their shop loyalty. Adolescents thought the price was economical, and they had less concept in 'price knowledge' due to their position. Unlike adults, adolescent's gender does not have effects on their 'economic concept. Male students also had high scores in 'economic concept' as much as female students did.

• Membrane and Water Treatment
• /
• 제11권2호
• /
• pp.159-166
• /
• 2020

In this study, the performance and antifouling properties of polysulfone (PSf) and polyvinylidene fluoride/polyvinylpyrrolidone (PVDF/PVP) membranes in a membrane bioreactor (MBR) were investigated. The membranes were prepared via phase inversion method, and then characterized by a set of analyses including contact angle, porosity and water flux and applied in a lab-scale MBR system. Soluble microbial product (SMP), extracellular polymeric substance (EPS), FTIR, gel permission chromatography (GPC) and particle size distribution (PSD) analyses were also carried out for MBR system. The results showed that the MBR with PSf membrane had higher hydrophobic organic compounds which resulted in formation of larger flocs in MBR. However, in this MBR had high compressibility coefficient of cake layer was higher (n=0.91) compared to MBR with PVDF/PVP membrane (n=0.8); hence, the fouling was more profound. GPC analysis revealed that compounds with molecular weight lower than 2 kDa are more formed on PSf membrane more than PVDF/PVP membrane. The results of FTIR analysis confirmed the presence of polysaccharide and protein compounds on the cake layer of both membranes which was in good agreement with EPS analysis. In addition, the results showed that their concentration was higher for the cake on PSf membrane.

• 한국콘텐츠학회논문지
• /
• 제1권1호
• /
• pp.59-67
• /
• 2001

컴퓨터를 비롯한 통신의 영역과 가전제품의 영역이 교차되면서 새로운 차원의 정보가전제품들이 등장하고 있으며 이들 제품들에게 있어 사용자 인터페이스는 매우 중요한 요소라 할 수 있다. 특히 영상기기류에 장착되는 OSD와 리모컨은 사용자 인터페이스의 핵심적인 요소로서 본체의 매력적인 스타일링 못지않게 심도깊은 연구가 필요한 부분이다. 그럼에도 불구하고 OSD 디자인에 대한 담당자나 영역이 불명확하여 회로기술자들이 단순기능의 이전모델부터 해온 경험과 단순한 직관을 바탕으로 사용자의 시각이 아닌 엔지니어의 시각에서 설계하여 왔다. 이에 본 연구에서는 기업에서의 개발사례를 바탕으로 인터페이스 디자이너에 의한 사용자 중심의 OSD 개발 프로세스를 규명하고 OSD의 특수성 즉 OSD가 제한된 용량의 마이컴과 메모리에 저장되어 제품에 내장되고 디스플레이되는 매체도 해상도에 제약이 있는 TV화면으로 하드웨어적인 사양에 많은 영향을 받으며, 입력장치가 리모컨으로 제한된 수의 입력버튼을 가지고 모든 조작이 가능해야 한다는 점 등 을 고려한 실행단계별 가이드라인을 제시한다.

• 한국군사과학기술학회지
• /
• 제23권1호
• /
• pp.76-86
• /
• 2020

Technology growth curve methodology is commonly used in technology forecasting. A technology growth curve represents the paths of product performance in relation to time or investment in R&D. It is a useful tool to compare the technological performances between Korea and advanced nations and to describe the inflection points, the limit of improvement of a technology and their technology innovation strategies, etc. However, the curve fitting to a set of survey data often leads to model mis-specification, biased parameter estimation and incorrect result since data through survey with experts frequently contain outlier in process of curve fitting due to the subjective response characteristics. This paper propose a method to eliminate of outlier from a technology growth curve using M-estimator. The experimental results prove the overall improvement in technology growth curves by several pilot tests using real-data in Defense Science and Technology Survey reports.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2011년도 추계학술대회
• /
• pp.88-90
• /
• 2011

국제수로기구는 수로분야의 다양한 자료를 일관되게 생산하고 활용하기 위한 범용 데이터 표준인 S-100을 개발하였으며, 이를 이용하여 수로분야 데이터 표준을 개발 중에 있다. 수로분야 데이터 요구사항 수용을 위해 포함 내용을 수정하였으며, 제품 표준을 위해 미진한 부분을 상세화 중에 있다. 본 연구에서는 S-100 표준의 개발현황과 요구사항에 따른 수정내역을 분석하였다. 또한 S-100 표준을 이용한 적용사례 분석을 통해 활용방안을 작성하였다.

• 기술혁신연구
• /
• 제13권2호
• /
• pp.179-205
• /
• 2005

This study reveals that the user industry has a limited role in being a source of technological capability in the case of the machine tool industry in Korea where the user industry is relatively more advanced than other capital goods industries. This study examines the sources of technological capability in terms of migration of workforces and flow of product development knowledge. Although the capital goods sector is generally regarded as being the sector where user-producer interaction is important, the user industry is not the seed-bed of technological capability for machine development. Users and producers interact in terms of expressing 'needs', mainly in the form of specifications. As a result of receiving unique specifications from users, the producer learns to react by making specific customised special purpose machines. The user's specification could include information o the imported machine originally used. When confronted with technical problems in developing a new machine, the producer accesses foreign sources of knowledge. This study's finding reveals that users of special purpose machines have a significantly clearer role in providing specifications than do users of general purpose machine tools. Most intensive interactive learning between users and producers in the production process is found in special purpose machine tools. From the empirical findings, policy implications are discussed.

• 한국전자거래학회지
• /
• 제2권1호
• /
• pp.21-37
• /
• 1997

As the complexity in design and manufacturing activities of distributed virtual enterprises rapidly increases, the issue of process management becomes more critical to shorten the time-to-market, reduce the manufacturing cost and improve the product quality. This paper proposes a unified framework to manage design and manufacturing processes in a distributed environment. We present a methodology which utilizes process flow graphs to depict the hierarchical structure of workflows and process grammars to represent various design processes and design tools. To implement the proposed concept, we develop a process management system which mainly consists of a cockpit and manager programs, and we finally address a preliminary implementation procedure based on the Object Modeling Technique. Since the proposed framework can be a formal approach to the process management by providing formalism, parallelism, reusability, and flexibility, it can be effectively applied to further application domains of distributed virtual enterprises.

• 제어로봇시스템학회논문지
• /
• 제15권7호
• /
• pp.742-752
• /
• 2009

Engineering design involves the specification of many variables that define a product, how it is made, and how it behaves applied to computer, communication and control fields. Before some variables can be determined, other variables must first be known or assumed. This fact implies a precedence order of the variables, and of the tasks of determining these variables consequently. Moreover, design of complex systems may involve a large number of design activities. In this paper, the activity-activity incidence matrix is considered as a representation of design activity analysis which mainly focuses on the precedence constraint with an object of doing IDEF3 in process-centered view. In order to analyze the activity-activity incidence matrix, a heuristic algorithm is proposed, which transforms an activity-activity, parameter-formula, and parameter-parameter incidence matrix into a lower triangular form. The analysis of the structured matrices can not only significantly reduce the overall project complexity by reorganizing few critical tasks in practice, but also aims at obtaining shorter times considering the solution structure by exploring concurrency.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.838-849
• /
• 2010

It is inevitable to control the systematic failure to obtain the software safety integrity of embedded software installed in rolling stock. Because it is not possible to assess systematic failure integrity by quantitative methods, SILs are used to group documentation, methods, tools and techniques throughout software development lifecycle which, when used effectively, are considered to provide an appropriate level of confidence in the realization of a system to a stated integrity level. Normally, safety approval process is through generic product, generic application and specification application for. For safety approval on generic application of software based system, it is required to apply the certified software processes from the planning stage for the assigned SIL. As such, we will develop project specific application with high safety integrity within time limit of contractual delivery schedule through software assessment to the modified area with the re-use of certified software module and documentation. At this point, Hyundai Rotem has developed software processes applicable to support SIL 4 based on EN50128 which was assessed and certified by TUV SUD. This paper introduces the Hyundai Rotem's detailed approach and prospective action to achieve software safety integrity level.