• 한국태양에너지학회 논문집
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• 제21권1호
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• pp.21-25
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• 2001

A methodology to predict the output performance of small hydro power using discharge of sewage treatment plant has been studied. Two sewage treatment plants existing in Chunrabuk-Do were selected and the output performance characteristics for these plants were analyzed, using developed model. As a result, it was found that the developed model in this study can be used to analyze the output characteristics for small hydro power using discharge of sewage treatment plant. Additionally, primary design specifications such as design flowrate, capacity, operational rate and annual electricity production were estimated and discussed for two plants.

• Water Engineering Research
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• 제2권1호
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• pp.11-19
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• 2001

A performance prediction model for Small Hydro Power(SHP) sites has been studied and developed. Twelve SHP sites were selected and the performance characteristics were analyzed by using the developed model. Also, primary design specifications such as design flowrate, plant capacity, operational rate were suggested and feasibility for small hydro power sites were estimated. It was found that the design flowrate is most important parameter to exploit SHP plant and the methodology developed in this study can be a useful tool to analyze the performance of SHP sites.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 추계학술대회
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• pp.569-578
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• 2008

The aim of this study is to propose economical safety driving speed index which those are geometric road status; examine the levels of which those cost-benefit of driving fuel expenditure; are search road safety design and operational technology for driving simulators. For the objective, we analyzed the current status of driving fuel expenditure and driving scenarios by the road alignments, and reviewed driving and technical specifications by the geometric types of road according to the implementation, and extended completion. Throughout the result of this study, diverse related driving information provision service, efficiently driving system is expected to be implemented in the national highway design system.

• ETRI Journal
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• 제43권2호
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• pp.173-183
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• 2021

As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.

• International Journal of Computer Science & Network Security
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• 제22권11호
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• pp.357-366
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• 2022

Artificial intelligence (AI) is the replication of human intelligence by computer systems and machines using tools like machine learning, deep learning, expert systems, and natural language processing. AI can be applied in administrative settings to automate repetitive processes, analyze and forecast data, foster social communication skills among staff, reduce costs, and boost overall operational effectiveness. In order to understand how AI is being used for administrative duties in various organizations, this paper gives a critical dialogue on the topic and proposed a framework for using artificial intelligence in organizations. Additionally, it offers a list of specifications, attributes, and requirements that organizations planning to use AI should consider.

• Journal of Positioning, Navigation, and Timing
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• 제13권1호
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• pp.35-44
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• 2024

This investigation primarily focuses on the generational characteristics of satellites utilized in the existing Global Navigation Satellite System (GNSS) and Regional Navigation Satellite System (RNSS), with a central emphasis on comparing the operational status of the latest generation satellites. Variations among satellite generations in physical attributes, energy consumption, and timekeeping are observed, enabling an exploration of the developmental trends over successive generations. Through a comparative analysis of the latest generation satellites, particularly in terms of performance, this study aims to furnish essential insights into the satellites employed within each system. Consequently, it will contribute to a foundational understanding of the past, present, and future GNSS satellites.

• 대한교통학회지
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• 제22권1호
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• pp.19-30
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• 2004

미래의 여객 수요가 예측이 되면, BHS 수요, 즉, 출발/환승/도착 수하물의 수, 시공되어야 하는 수송 라인의 수, 수하물을 항공기로 이동하는데 사용 되는 컨테이너의 수, 수하물 수취를 위한 수취대의 수 등이 반드시 산정되어 설계에 반영되어야 하므로 공항을 건설함에 있어 여객 수하물의 물동량을 산정하는 것은 중요한 분석 요소 중의 하나이다. 본 연구에서는 공항 설계 시 정확한 BHS 수요 산정을 하기 위하여 Time-based distribution table을 기반으로 하는 수학적 모델을 제안한다. BHS 수요가 산정 되면, 장비들의 실제 사양들(처리량 등)을 적용하여 관련 설비들의 적정 규모를 산정할 수 있다. 본 연구에 제시된 모델은 IIA(인천 국제 공항)의 운영 조건을 합리적으로 잘 반영하고 있고, 더욱이 장비들의 사양들은 최신의 자료들이므로 보다 효율적이고 현실적인 BHS 설계 및 설비 선정이 가능하다.

• 한국전자파학회논문지
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• 제25권3호
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• pp.311-318
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• 2014

소형 위성 발사체 나로호의 전자파 적합성 성능은 탑재 위성과 우주센터에 설치되는 지상 장비, 그리고 다른 무선통신망 사이에서 정상적인 동작을 보장하도록 확보되고 검증되어야 한다. 전자파 적합성 성능을 검증하기 위해서는 서브 시스템과 시스템에 대한 적절한 시험 규격과 방법, 그리고 절차가 발사체의 운용 특성과 전자기 환경을 고려하여 수립되어야 한다. 그리고 프로그램 종료단계까지 결정된 규격에 따라 지속적으로 전자파 적합성 특성을 유지 관리하는 것이 요구된다. 본 논문에서는 나로호의 발사체 개발 전 주기 동안 수행된 순차적인 관리 업무를 기술하고, 나로호와 각 서브 시스템의 각 모델에 대한 단계별 시험계획뿐만 아니라, 시험 방법, 규격, 검증시험 결과 등이 제시된다. 또한, 멀티팩션 분석에 대한 결과를 기술한다.

• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.103-111
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• 2021

In modern society, digital lifestyles are spreading to minimize contact with people and to receive contactless information. The spread trend has established an unmanned distribution system in which transactions through contactless technologies such as kiosks and chatbots are activated in face-to-face transactions with sellers and consumers. In order to streamline logistics supply worldwide, digital new deal based joint logistics hubs, unmanned courier storage platforms, and fresh logistics based last mile services have been developed into unmanned logistics systems, focusing on the intelligent logistics system automation process. Unmanned courier storage system installed in urban areas and home to daily logistics where volume is concentrated are provided with fresh logistics services through cold chain and receiving freights in contactless environments. Development is also underway to minimize safety accidents caused by courier services, such as managing various information based on the integrated control system. This paper defines the concept of integrated operation for the development of a platform for contactless unmanned courier storage device developed into next-generation logistics system. In addition, we intend to develop systems engineering-based output for deriving safety requirements and specifications by identifying risk sources that may occur in the operational scenario. Therefore, the goal is to establish a foundation for safety and reliability between interfaces of logistics systems to be installed in apartment and subway station environments that want to provide unmanned logistics services to various consumers.

• 한국초전도ㆍ저온공학회논문지
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• 제25권3호
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• pp.49-55
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• 2023

This paper presents the design of a re-liquefaction system as a BOG (boil-off gas) handling process in liquid hydrogen transport vessels. The total capacity of the re-liquefaction system was assumed to be 3 ton/day, with a BOR (boil-off rate) of 0.2 %/day inside the cargo. The re-liquefaction cycle was devised using the He-Brayton Cycle, incorporating considerations of BOG capacity and operational stability. The primary components of the system, such as compressors, expanders, and heat exchangers, were selected to meet domestically available specifications. Case studies were conducted based on the specifications of the components to determine the optimal design parameters for the re-liquefaction system. This encompassed variables such as helium mass flow rate, the number of compressors, compressor inlet pressure and compression ratio, as well as the quantity and composition of expanders. Additionally, an analysis of exergy destruction and exergy efficiency was carried out for the components within the system. Remarkably, while previous design studies of BOG re-liquefaction systems for liquid hydrogen vessels were confined to theoretical and analytical realms, this research distinguishes itself by accounting for practical implementation through equipment and system design.