• 제목/요약/키워드: Technological Feasibility

검색결과 109건 처리시간 0.022초

An Improved One Cycle Control for Active Power Filters under Non-Ideal Voltage Conditions

  • Wang, Lei;Ren, Chunguang;Yang, Yu;Han, Xiaoqing;Wang, Peng
    • Journal of Power Electronics
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    • 제16권6호
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    • pp.2350-2358
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    • 2016
  • The one cycle control (OCC) scheme for active power filters (APFs) has shown excellent harmonic suppression and implementation simplicity. However, its real world application is limited because the non-ideal supply voltage for APFs can influence its performance so that the source currents are still distorted after compensation. This paper proposes a modified one cycle control (MOCC) scheme to improve the performance of three-phase shunt APFs under non-ideal supply voltage conditions. In this paper a detailed mathematical derivation has been presented and the key control law of the MOCC has been developed for adaption to the non-ideal supply voltages, following the control philosophy of simplicity. A relatively simple sequence filter is introduced to extract the harmonic components of supply voltages. The modified scheme can be easily implemented. The proposed control strategy has excellent performance and a 5kVA APF hardware platform has been implemented to validate the feasibility and performance of the proposed strategy.

Sliding Mode Control for Current Distribution Control in Paralleled Positive Output Elementary Super Lift Luo Converters

  • Kumar, Kuppan Ramash;Jeevananthan, Seenithangam
    • Journal of Power Electronics
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    • 제11권5호
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    • pp.639-654
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    • 2011
  • This paper presents a Current Distribution Control design for Paralleled Positive Output Elementary Super Lift Luo Converters (PPOESLLCs) operated in Continuous Conduction Mode using a Sliding Mode Controller (SMC). Manipulating the higher current requirement of the load through the paralleling of POESLLCs, results in a current inequality. This is mainly due to dissimilarities in the power semiconductor switches and circuit components used in POESLLCs, which may lead to converter failures. In order to balance the proper load current sharing and the load voltage regulation of PPOESLLCs, a SMC is developed. The SMC is designed for the inherently variable-structured of POESLLCs by using the state-space average based model. The static and dynamic performance of the developed controller with PPOESLLCs is validated for its robustness to perform over a wide range of operating conditions through both a laboratory prototype and MatLab/Simulink models, which are compared with a Proportional-Integral (PI) controller. Theoretical analysis, simulation and experimental results are presented to demonstrate the feasibility of the developed SMC along with the complete design procedure.

특허정보를 활용한 산업융합성 평가 방법론 : 기술연관분석 (A Methodology to Evaluate Industry Convergence Using the Patent Information : Technology Relationship analysis)

  • 김지은;이성주
    • 대한산업공학회지
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    • 제39권3호
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    • pp.212-221
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    • 2013
  • As the convergence among technologies is reorganizing industry sectors, it is quite important to evaluate the probability of technological convergence, and to analyze how the technologies in a certain industry sector affect the same or other industry sectors. As a result, the large number of studies have been focused on the industry convergence. However, most of them have dealt mainly with case studies or strategy and policies and few efforts have been made to study it using quantitative data. The investigation of industry convergence using quantitative data will help understand the characteristics of industry and forecast the future of the industry from an objective point of view. Therefore, this research proposes a methodology to evaluate the possibilities of industry convergence using patent data. In particular, we emphasize the possibilities of technology convergence and suggest a technology relationship matrix to evaluate the technology convergence, as an antecedent of industry convergence. The feasibility and utility of the suggested methodology was verified with a case study on the convergence of IT and BT. The research results are expected to provide a useful guideline for developing a measure of convergence.

Recovery of ammonia from wastewater by liquid-liquid membrane contactor: A review

  • Jang, Yoonmi;Lee, Wooram;Park, Jaebeom;Choi, Yongju
    • Membrane and Water Treatment
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    • 제13권3호
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    • pp.147-166
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    • 2022
  • Liquid-liquid membrane contactor (LLMC), a device that exchanges dissolved gas molecules between the two sides of a hydrophobic membrane through membrane pores, can be employed to extract ammoniacal nitrogen from a feed solution, which is transported across the membrane and accumulated in a stripping solution. This LLMC process offers the promise of improving the sustainability of the global nitrogen cycle by cost-effectively recovering ammonia from wastewater. Despite recent technological advances in LLMC processes, a comprehensive review of their feasibility for ammonia recovery is rarely found in the literature. Our paper aims to close this knowledge gap, and in addition to analyze the challenges and provide potential solutions for improvement. We begin with discussions on the operational principles of the LLMC process for ammonia recovery and membrane types and membrane configurations commonly used in the process. We then assess the performance of the process by reviewing publications that demonstrate its practical application. Challenges involved in the implementation of the LLMC process, such as membrane fouling, membrane wetting, and chemical requirements, are presented, along with discussions on potential strategies to address each. These strategies, including membrane modification, hybrid process design, and process optimization based on cost-benefit analysis, guide the reader to identify key areas of future research and development.

How Chinese Online Media Users Respond to Carbon Neutrality: A Quantitative Textual Analysis of Comments on Bilibili, a Chinese Video Sharing Platform

  • Zha Yiru
    • Asian Journal for Public Opinion Research
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    • 제11권2호
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    • pp.145-162
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    • 2023
  • This research investigates how users of Bilibili, a video sharing website based in China have responded to carbon neutrality. By conducting quantitative textual analyses on 3,311 comments on Bilibili using LDA topic extraction and content statistics, this research discovers that: (1) Bilibili users have assigned more weight to geopolitical topics (56.3%) than energy (22.0%) and environmental topics (21.7%). (2) When assessing carbon neutrality, Bilibili users considered geopolitical (53.8%) and energy factors (15.8%) more heavily than factors related to the class (9.2%), economy (8.9%), environment (8.7%), and definition (3.6%). (3) More Bilibili users had negative (64.6%) attitudes towards carbon neutrality, with only a small portion of them expressing positive (26.8%) and neutral (8.6%) attitudes. (4) Negative attitudes towards carbon neutrality were mainly driven by geopolitical concerns about the West's approach to China, other countries' free-riding on China's efforts and the West's manipulation of rules, doubts about the feasibility of energy transition and suspicion of capitalists exploiting consumers through this concept. This research highlights the geopolitical concerns behind the environmental attitudes of Chinese people, deepening our understanding to psychological constructs and crisis sensitivity of Chinese people towards environmental issues.

Revolutionizing Nepal's Transportation: The Potential of Advanced Air Mobility (AAM) in Overcoming Geographical Challenges

  • Leeladhar Joshi;Kwang-Byeng Lee
    • 한국항공운항학회지
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    • 제32권2호
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    • pp.37-47
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    • 2024
  • This paper examines the unique transportation challenges posed by Nepal's diverse and rugged terrain, which significantly hampers socio-economic development due to its negative impact on infrastructure, trade, and accessibility. Despite ongoing efforts to enhance road and traditional air transport systems, Nepal's geographic and environmental conditions continue to obstruct efficient connectivity, particularly in rural and remote areas. This study proposes Advanced Air Mobility (AAM) as a transformative solution, leveraging recent technological advancements in unmanned aerial vehicles (UAVs) and electric vertical takeoff and landing (eVTOL) aircraft. By conducting a comprehensive analysis of Nepal's current transportation infrastructure and the feasibility of AAM implementation, the paper highlights the potential benefits of AAM, including improved accessibility, economic growth, and environmental sustainability. Furthermore, it addresses the anticipated challenges and regulatory considerations necessary for integrating AAM into Nepal's transportation network. Through a multidisciplinary approach, this research aims to contribute to the discourse on overcoming transportation barriers in mountainous regions, offering policy recommendations and identifying areas for future study to facilitate the adoption of AAM in Nepal and similar contexts worldwide.

인공지능 분야 국방 미래 신기술 예측에 관한 실증연구 (An Empirical Study on the Prediction of Future New Defense Technologies in Artificial Intelligence)

  • 안진우;노상우;김태환
    • 한국산학기술학회논문지
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    • 제21권9호
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    • pp.458-465
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    • 2020
  • 인공지능의 기술적 진보는 통신·물류·보안·의료 등 다양한 산업분야에 영향을 미치고 있으며, 경제성·효율화·상용기술과의 연계방안과 관련된 연구개발이 중점적으로 이루어지고 있다. 국방 분야에서도 다차원 동시 통합전, 유·무인 복합전, 국지성 비대칭전 등 전쟁수행 개념이 발전함에 따라 전장인식·지휘통제·전력운용·의사결정 지원 등의 분야에 인공지능 역량을 적용하기 위한 개념설계와 실적용을 위한 과제 기획을 지속 추진 중이다. 전략적 관점에서 미래 전장 환경 및 전쟁 수행 방식의 변화를 예측하고, 선도적 대응을 위해 군사력 발전 방향을 설계·기획하는 것은 포괄적 미래 위협에 대비하기 위한 기본요소일 뿐만 아니라, 한정된 예산/시간 대비 최적의 효율을 도출할 수 있다는 점에서 필수불가결한 요소이다. 이러한 관점에서 본 연구는 국방 분야의 활용 가능성이 높은 잠재력 있는 미래기술을 발굴하고 연구개발에 적용하기 위한 기술주도형 기획의 일환으로 수행되었다. 본 연구에서는 국방 미래기술 조사를 위해 수행되었던 연구 자료를 바탕으로 기존 국방 연구과제들과의 중복성, 기술의 실현가능성 등을 고려하여 후속 연구가 필요한 미래 신기술을 예측하였다. 또한 선정된 인공지능 분야 국방 미래 신기술과 평가지표 간 유의미성을 확인하기 위해 실증연구를 수행하였다.

RFID 개인정보 영향평가지수 개발 (An Impact Assessment Index for the RFID Privacy)

  • 한필구;강병구
    • 정보관리연구
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    • 제40권1호
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    • pp.69-86
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    • 2009
  • 최근 정보통신 분야의 가장 큰 패러다임은 유비쿼터스 컴퓨팅(ubiquitous computing)이다. 이는 유비쿼터스 사회(ubiquitous society)를 실현하는 기반 기술로서 사회, 경제, 문화 등 모든 분야에 긍정적인 영향력을 미치게 될 것이나, 유비쿼터스 사회로의 진입은 개인 프라이버시를 침해할 수 있다는 우려의 목소리도 함께 나타나고 있다. 따라서 이를 보호하기 위한 법적, 기술적 규제 방안의 존재는 향후 RFID 기술 및 산업의 확산에 큰 장애요인이 될 것이며, 문제 해결을 위해 기술적인 방법으로만 접근한다면 기업 측면에서는 막대한 비용과 기술력을 투자해야만 할 것이다. 이에 본 연구에서는 한필구(2006)가 개발한 "RFID 활용단계별 개인정보보호 영향평가(안)"의 8개의 RFID 활용단계, 단계별 과정, 점검사항 그리고 85개의 평가항목들을 RFID 개인정보 영향평가를 측정할 수 있는 지표로 선정하여, 해당전문가를 대상으로 설문조사를 통한 객관적 자료를 활용해 RFID 개인정보 영향평가지수를 개발하고자 한다. 이는 RFID 관련 분야 기업에는 타당성과 신뢰성 있는 자료를 제공할 수 있을 것이며, RFID 개인정보에 관한 정책 수립에도 활용할 수 있을 것이다. 또한 RFID 활용에 있어서 개인정보에 대한 진단 도구로서 하나의 기준 및 유비쿼터스 사회의 기반 구축에 기여할 것으로 기대한다.

A FUNDAMENTAL STUDY TO DEVELOP STANDARD TECHNOLOGY CRITERIA FOR IT-CONSTRUCTION FUSION TECHNOLOGIES, TO BE APPLIED TO A U-CITY

  • Kyoon-Tai Kim;Jae-Goo Han;Chang-Han Kim
    • 국제학술발표논문집
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    • The 3th International Conference on Construction Engineering and Project Management
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    • pp.1352-1358
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    • 2009
  • As the demand for a convergence between construction technologies and IT is on the rise, as seen in the visualization of U-City construction, studies on the ways in which IT in should be utilized in the building and construction field have been continuously and actively performed. However, there has been almost no development of standardized technology criteria relating to the life cycle of a building (planning, design, construction, and maintenance). That is, there are almost no examples of efforts made to combine construction technology and IT in a fundamental way, considering the environment, the facility, its spatial characteristics, engineering, materials, and structure, aspects that are commonly required not only for interior spaces but also for exterior construction of U-City. Despite the fact that a state-of-the-art infrastructure has been built, and the competency of users with the cutting-edge technology, composite studies on technologies, facilities, services and spaces are still lacking, and basic research on the composite operation method including compatibility and linkage between facilities and services within a U-City has been insufficient as well. It is generally known that by fusing IT with construction technologies, the total period of construction taken can be reduced and construction expenses can be curtailed, while construction quality can be improved. For this reason, it is vital to prepare a standardized base to connect cutting-edge IT with the construction technologies. In preparing such a base, the most urgent issue is to develop standardized technology criteria. The ultimate objective of this research is to establish the technological criteria system required to apply construction-IT fused technologies to U-Cities, and to develop the technological criteria for the design, construction and maintenance of the U-Cities. This paper, whose objective is to establish development strategies for construction-IT fused technologies by way of analyzing the criteria for conventional construction projects, the necessity of criteria for construction-IT fused technologies, and the current status of U-Cities' development, is the underlying research for this purpose. The strategies established are expected to be utilized in establishing the system of criteria for construction-IT fused technologies, and to contribute to a knowledge base in the construction-IT field. In addition, based on the strategies established, criteria for construction-IT fused technologies, such as design criteria and construction standards, will be developed, and by applying these criteria and standards, the ultimate objectives of U-Cities, which are the enhancement of urban competitiveness and the satisfaction of residents, will be attained

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푸르푸랄의 화학적 촉매전환을 통한 테트라히드로푸르푸릴 알코올 생산 공정 개발 및 경제성 평가 (Process Development and Economic Evaluation for Catalytic Conversion of Furfural to Tetrahydrofurfuryl Alcohol)

  • 변재원;한지훈
    • Korean Chemical Engineering Research
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    • 제55권5호
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    • pp.609-617
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    • 2017
  • 목질계 바이오매스는 바이오 연료 및 바이오 화학제품 생산을 위한 재생 가능 자원이다. 푸르푸랄(furfural, FF)은 목질계 바이오매스의 헤미셀룰로스로부터 화학적 촉매전환으로 유도되는 주요한 플랫폼 케미칼이다. 테트라히드로푸르푸릴 알코올(Tetrahydrofurfuryl alcohol, THFA)은 FF의 유도체로 열적 화학적 안정성을 지닌 친환경 용매로 이용 가능하다. FF를 THFA로 전환하는 실험적 연구가 다수 존재함에도 불구하고, FF로부터 THFA의 대량생산에 관한 경제적 실현가능성에 관한 연구는 거의 수행되지 않았다. 개발된 전환기술의 상용화 단계에서 기술적 병목점 확인과 스케일업 문제의 해결을 위한 정보를 얻기 위해 실증플랜트 규모의 연구가 필요하다. 본 연구에서는 FF의 THFA로의 화학적 촉매전환에 대해 공정 시뮬레이션 및 기술경제성 평가가 수행되며, 3가지 단계(통합 공정 디자인, 열 통합, 경제성 평가)를 거친다. 실험연구 결과를 기반으로 전환공정과 분리공정을 포함하는 실증플랜트 규모의 통합공정이 설계된다. FF 처리량은 일일 255톤이며, FF로부터 THFA로의 수율은 63.2~67.9 mol%이다. 통합공정에 대해 열 통합을 수행하여 가열요구량을 최초 대비 14.4~16.4% 감소시킬 수 있었다. 최종적으로 경제성 평가를 통해 전체 공정의 주요 비용원을 분석하고 THFA의 최소판매가격을 결정하였다. 개발된 공정에서 생산되는 THFA의 최소판매가격은 1톤당 2,120~2,340 달러로, 현재 THFA의 시장 가격에 근접한다.