• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2288-2297
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• 2023

Current designs of both large reactor units and small modular reactors utilize a nuclear fuel with increasing enrichment. This increasing demand for better nuclear fuel utilization is a challenge for nuclear fuel handling facilities. The operation with higher enriched fuels leads to reduced reserves to legislative and safety criticality limits of spent fuel transport, storage and final disposal facilities. Design changes in these facilities are restricted due to a boron content in steel and aluminum alloys that are limited by rolling, extrusion, welding and other manufacturing processes. One possible solution for spent fuel pools and casks is the burnup credit method that allows decreasing very high safety margins associated with the fresh fuel assumption in spent fuel facilities. This solution can be supplemented or replaced by an alternative solution based on placing the neutron absorber material directly into the fuel assembly, where its efficiency is higher than between fuel assemblies. A neutron absorber permanently fixed in guide tubes decreases system reactivity more efficiently than absorber sheets between the fuel assemblies. The paper summarizes possibilities of fixed neutron absorbers for various nuclear fuel and fuel handling facilities. Moreover, an absorber material was optimized to propose alternative options to boron. Multiple effective absorbers that do not require steel or aluminum alloy compatibility are discussed because fixed absorbers are placed inside zirconium or steel cladding.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.233-235
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• 2020

본 논문은 40 kV 나노초 펄스발생을 위한 모듈형 solid-state Marx modulator(SSMM) 설계에 대해 기술한다. 가속기 및 플라즈마 어플리케이션과 같은 다양한 응용분야에 요구되는 전압 및 전류 사양을 만족시키기 위해 10 kV(출력 전압), 50 ns(펄스폭), 20 ns(상승&하강 시간), 100 kHz(반복률)의 사양을 만족하는 단위모듈기반으로 모듈형 설계를 제안한다. 독립적인 제어가 가능한 4개의 단위모듈을 기반으로 제안된 SSMM은 임의의 출력 파워 및 임피던스를 만족시킬 수 있는 장점을 가지고 있다. 예를 들어, 모든 단위모듈의 위상을 같게 했을 때 출력전압을 증가시킬 수 있으며 각 모듈의 위상을 지연하였을 경우는 펄스의 반복률을 크게 높일 수 있다. 개발된 SSMM은 직렬 스택 MOSFET의 스위칭 성능을 향상시키기 위해 게이트 구동 회로는 동기 신호와 구동 전력을 제공하는 1 턴 변압기로 설계되었다. 출력 펄스의 폭과 하강시간을 최소화하기 위해 다이오드 대신 기생 커패시턴스에 저장된 에너지를 빠르게 방출하는 액티브 풀다운 회로가 적용되었다. 또한, 출력 펄스의 빠른 상승을 달성하기 위해 게이트의 라인 인덕턴스를 최소화하고 모든 게이트 신호의 동기화는 필수적이다. 개발된 ns급 펄스전원장치는 단위모듈을 기반으로 최대 펄스전압이 40 kV 까지 출력이 가능하며 이에 대한 상세설계 및 구현은 실험결과를 바탕으로 검증한다.

• Korean Architects
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• s.615
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• pp.28-31
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• 2020

도입까지 시간이 걸릴 것이라고 예측됐던 건설정보모델링(BIM : Building Information Modeling, 이하 BIM)이 어느새 성큼 다양한 분야에 진입했다. 영국, 싱가포르, 미국 등 해외에서는 이미 공공사업 시 BIM을 적극적으로 활용하고 있다. 우리나라 또한 2018년 국토교통부에서 '스마트 건설기술 로드맵'을 마련한 후 공공사업에 BIM을 단계적으로 도입해왔다. 대부분의 발주기관들은 오는 2025년까지 공공사업에 BIM을 전면 도입한다는 계획이다. 성균관대학교 공과대학 건설환경공학부 및 미래도시융합공학과 교수이자 국제건설자동화학회의 종신 상임이사인 권순욱 교수는 '스마트 건설 관리' 연구자이자 국내외에서 활동 중인 CM, BIM의 권위자다. 관련 분야의 책 8권과 100편 이상의 논문을 집필하고 30여 개의 특허·소프트웨어 등록을 보유하고 있다. 텍사스 오스틴 대학교 토목공학 박사 출신으로, 삼성물산, 한국건설기술연구원 등 일반 기업과 국가기관에서 실무와 이론을 두루 경험하며 경력을 쌓았다. 건설연구개발사업, 첨단 융복합 건설기술 등 다수의 국가 건설 R&D에 참여해 초고층 자재, 안전 모니터링, BIM 프로세스 표준개발 등의 시스템을 개발하기도 했다. 해외 연구자들과의 교류에도 적극적이다. 세계 석학들과 '노령 공학' 관련 영문교과서를 공동 집필(스마트주택 챕터 담당)했고, 2016년과 2019년엔 국제건설자동화학회와 국제프로젝트관리학회의 연사 자격으로 강단에 섰다. "영국, 싱가포르 등에선 공공사업을 100% BIM으로 발주하기 시작했습니다. 우리나라 정부도 비슷한 길을 가고 있습니다. 일정 규모의 발주 물량이 안정적으로 나오는 공공기관에서 그렇게 한다는 것은 국가가 전체 패러다임을 바꾸겠다는 의지 아닐까요?" 6월 10일 그의 연구실에서 권순욱 교수를 만나 BIM의 현황과 전망에 대해 들어봤다.

• Journal of the Korean Institute of Rural Architecture
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• v.26 no.2
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• pp.9-16
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• 2024

In order to achieve carbon neutrality in the architectural field by 2050, this study analyzed the energy impact proportional to CO2 emissions of each technique, such as design methods, the properties of building structures, prefabrication methods, passive houses, and active facilities. In addition, the results were presented quantitatively in terms of carbon reduction, and corresponding housing cases were analyzed. The research method is limited to residential buildings at the Passive House energy level, and carbon reduction techniques and elements in architecture are examined through various literature and materials, and empirical cases are analyzed to determine the specific possibility of realizing carbon reduction in architecture. We want to secure it. Based on these analysis results, it was possible to suggest that it is possible to explore various approaches to carbon reduction in future residential construction. By combining the most efficient techniques according to the energy reduction level or goal setting of the building in question, we expect the possibility of achieving the goal of carbon reduction in the residential sector more realistically.

• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.3315-3329
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• 2024

Small Modular Reactors (SMRs) adopt the Helically Coiled Once-Through Steam Generators (OTSG) extensively for its compactness and higher heat transfer efficiency. As a heat exchanger between the primary side (reactor coolant system) and the secondary side (feedwater and steam system) of nuclear steam supply system, the inlet/outlet conditions both of shell side and tube side of OTSGs have significant impacts on overall system response. Considering the flexible operation of SMRs and heat application by extracting steam, a simulation tool for accurate prediction of the OTSG dynamic behaviors would be required for optimizing design and control. In this study, the OTSG dynamic simulation model has been developed. Mathematical governing equation has been derived by using moving boundary approach and a simulation module has been developed by using Modelica Language. The developed module has been compared with publicly available experimental results and benchmarked with MARS-KS calculation results. Also, it has been incorporated into the integrated SMR model (i.e., reactor core, primary side, secondary side) and dynamic behaviors with reactivity feedback and heat balancing have been investigated. In both of steady-state and transient conditions, it shows the promising accuracy.

• Journal of Auto-vehicle Safety Association
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• v.16 no.3
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• pp.7-17
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• 2024

Ensuring an automated fallback strategy in response to malfunctions during the execution of the Dynamic Driving Task (DDT) is imperative for Level 4 autonomous driving systems. While Triple Modular Redundancy (TMR) represents a prominent Fail-Operational structure, its practical application to multiple systems is constrained by the substantial increase in costs. In this paper, we propose a pragmatic Fail-Operational safety concept utilizing on-board camera sensors and the Vehicle-to-Infrastructure (V2I) communication module, known as the On-Board Unit (OBU), to provide traffic signal information within the vehicle. The viability of the designed safety concept is validated through error injection simulations. This approach addresses the practical limitations associated with applying Fail-Operational functionality to numerous systems due to the considerable cost escalation. Leveraging camera sensors and V2I communication modules presents a practical and cost-effective solution for maintaining operational safety in Level 4 autonomous driving systems, particularly when responding to malfunctions in the DDT.

• Science of Emotion and Sensibility
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• v.13 no.3
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• pp.467-474
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• 2010

Recently, Study of functional clothing for Vital sensing is focused on reducing artifact by human motions, in order to enhance the electrocardiogram(ECG) sensing accuracy. In this study, considering the factors for each element found from the analysis, a 3-lead electrode inside textile embroidered with silver yarn was developed, and draft designs off our types of vital-signal sensing garments, which are 'chest-belt typed' garment, 'cross-typed' garment 'x-typed' garment and 'curved x-typed' garment, were prepared. The draft designs were implemented on a sleeveless male shirt made of an elastic material so that the garment and the electrodes can remain closely attached along the contour of the human body, and the acquired data was sent to the main computer over a wireless network. In order to evaluate the effects caused by body movements and the ECG-sensing capability for each type in static and dynamic states, displacements were measured from one and two dimensional perspectives. ECG measurement evaluation was also performed for Signal-to-noise ratio(SNR) analysis. Applying the experimental results, the draft garment designs were modified and complemented to produce two types of modular approaches 'continuous-attached' and 'insertion-detached' for the ECG-sensing smart clothing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.284-287
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• 2000

Recently, developing medical devices have a tendency becoming the module for satisfying user's mutual complex needs. Because the most effective method for the observation of patients condition a diagnosis and a treatment is collecting data from various devices and controling operation following it. Module tendency is more popular due to manage easily totally many individual systems. This study implemented communication protocol to control by one control system connecting modular medical devices. Implemented system consist of one master module controlling all module and managing communication and many Slave modules. Communication between each modules introduced SPI(Serial Peripheral Interface) among many synchronous serial communication methods for the exact transmission and receipt of data. All communication executes by packet format. This can detect error. And, this protocol introduced PNP(Plug And Play) function that auto-detect connecting or removing module during running. This protocol exactly transmitted and received in faster speed more than 1Mbps. And in practical application to the ventilator this confirmed to give and take real-time data. And various functions by th central control system is implemented in this protocol.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.3-11
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• 2016

The concern about hollow core PC slab has been increased to improve the workability during a construction of building by reducing self weight of structural members. In this manner, recently, TRS (Tripple Ribs Slab) was developed as a new type of half PC slab system. TRS member consists of the triple webs and the bottom flange prestressed by strands. The slab system is completed by casting of topping concrete on the TRS after filling styrofoam between the webs. This paper, presents a flexural experiment to investigate the flexural capacity of the TRS. Five full scale TRS members were made and tested under simple support condition to be failed by flexure and their strength was evaluated by code equations; the variables in the test are the depth and the presence of topping or raised spot formed when slip-forming. In addition, a nonlinear sectional analysis was performed for the specimens and the result was compared with the test results. From the study, it was found that the TRS has enough flexural strength and ductility to resist the design loads and its strength can be suitably predicted by using code equations. The raised spot did not affect the strength so that the spot need not to be removed by doing additional work. For the more accurate prediction of TRS's flexural behavior by using nonlinear sectional analysis, it is recommended to consider the concrete's brittle property due to slip-forming process in the modeling.

• Elastomers and Composites
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• v.44 no.2
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• pp.164-174
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• 2009

PA66/EPDM/PP-g-MA and PA66/EPDM-g-MA/PP-g-MA composites were manufactured by a modular intermeshing twin screw extruder for enhanced low temperature impact resistance with different content of PP-g-MA. The results showed that composite containing 90 wt% of PA66, 8 wt% of EPDM-g-MA, and 2 wt% of PP-g-MA has a optimum value in the thermal and mechanical properties. The characteristics of the composites were analyzed by TGA, DSC, and SEM. From above results, we established that the low interfacial strength and the impact resistance at low temperature shown in a pre-existing PP/EPDM composite were enhanced by grafting with compatibilizer such as maleic anhydride. These results show the possibility of local manufacturing process and cost down with optimum screw configuration for best mixing quality in the twin screw extruder.