• International Journal of Computer Science & Network Security
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• 제22권1호
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• pp.139-148
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• 2022

Research into wireless sensor networks (WSNs) is a trendy issue with a wide range of applications. With hundreds to thousands of nodes, most wireless sensor networks interact with each other through radio waves. Limited computational power, storage, battery, and transmission bandwidth are some of the obstacles in designing WSNs. Clustering and routing procedures have been proposed to address these concerns. The wireless sensor network's most complex and vital duty is routing. With the Greedy Perimeter Stateless Routing method (GPSR), an efficient and responsive routing protocol is built. In packet forwarding, the nodes' locations are taken into account while making choices. In order to send a message, the GPSR always takes the shortest route between the source and destination nodes. Weighted directed graphs may be constructed utilising four distinct distance metrics, such as Euclidean, city block, cosine, and correlation distances, in this study. NS-2 has been used for a thorough simulation. Additionally, the GPSR's performance with various distance metrics is evaluated and verified. When compared to alternative distance measures, the proposed GPSR with correlation distance performs better in terms of packet delivery ratio, throughput, routing overhead and average stability time of the cluster head.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.1-9
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• 2022

The structure and operating principle of the 2-speed shift reducer were explained, the allowable bending stress value of the material was compared with the analysis result through FM structural analysis program, and the average stress distribution value of von Mises was performed on the gear root atmosphere. The structural safety of the 2-speed planetary gear reducer was verified through FM structural analysis. The natural frequency was calculated by applying the specifications of the planetary gears of the 2-speed gearbox, and the critical speed of resonance was calculated by calculating the natural frequency and the transmission error of the engaged gear pair. As a result of analyzing the critical speed, since it is formed higher than the actual operating speed range, it is considered safe because there is no resonance problem due to the suggested specifications of the planetary gears of the 2-speed shift reduction.

• 소성∙가공
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• 제32권3호
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• pp.122-128
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• 2023

As electric vehicles (EV) have increasingly replaced the conventional vehicles with internal combustion engines (ICE), most of automotive makers are actively devoting to the technology development of EV parts. Accordingly, the manufacturing process for power source has been also shifting from engine/transmission to EV motor/reducer system. However, lack of experience in developing the EV motor still remains as a technical challenge. In this paper, we employed the forming simulation based on finite element modeling to solve this problem. In particular, in order to increase the accuracy of the forming simulation, we introduced the elastic-plastic constitutive model parameters for polymer-copper hybrid wire by investigating the individual strain-stress curves, and elastic modulus of polymer and copper. Then, the reliability of modeling procedure was confirmed by comparing the simulated results with experiments. Finally, the identified mechanical properties and finite element modeling were applied to a hairpin forming process, which involves multiple deformation paths such as bending, pressing, widening, and twisting. The proposed numerical approach can replace common experience or experiment based trials by reducing production time and cost in the future.

• 한국시뮬레이션학회논문지
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• 제19권2호
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• pp.107-118
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• 2010

자동차 제조업은 수천 가지의 다른 구성품 또는 부품의 조립이 필요한 복잡한 생산시스템이다. 엔진과 트랜스미션은 자동차의 동력을 담당하는 주요 구성품이다. 엔진의 경우 생산공정이 대부분 유사한 공정들로 구성되어 있음에도 불구하고 공장별로 생산시스템의 배치안은 상이하다. 그 이유는 각 공장마다 기계들을 어떠한 직렬구조와 병렬구조를 조합하여 배치하는지에 대한 개념이 다르기 때문이다. 이 논문에서는 서로 다른 공장에서 적용하고 있는 세 종류의 엔진 라인을 소개한다. 그리고 시뮬레이션을 이용하여 각 라인의 설계개념이 라인의 성과에 미치는 영향에 대해 비교분석하고자 한다.

• 한국산업정보학회논문지
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• 제14권1호
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• pp.9-16
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• 2009

본 논문에서는 전기뇌관이 설치된 탄약에 유도되는 전자파 수신특성을 분석하기 위한 방법을 제안한다. 이 방법에서는 전기뇌관이 설치된 탄약을 수신 안테나로 모델링하고 안테나 이득을 시뮬레이션 또는 실험에 의해 구한다. 구해진 전기뇌관의 이득을 안테나 결합공식에 넣어 전기뇌관에 유도되는 전파전력을 구한다. 매우 근접한 거리에서의 전파수신 특성은 반파장 다이폴과 전기뇌관 모형 사이의 전력계수를 측정함으로써 구해진다. 제안된 방법을 사용하여 105 mm 전차탄약 뇌관의 전파수신 특성을 구하고 이로부터 900 MHz 대역 RFID 리더기에 대한 뇌관의 안전성을 분석하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.195-197
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• 2022

본 논문에서는 공공기관 또는 행정부 소속기관들이 공통으로 고민하는 기업 내부 인터넷망에서의 외부상용 메일시스템 사용에 대한 원천적 차단 방법론에 관해 연구해보고자 한다. 기존에 사용되는 blacklist 기반의 차단 방식에 대한 한계를 확인하고 메일발송 웹페이지의 패킷 분석을 통해 메일 전송이 사용되는 구분자를 추출하여 whitelist기술을 적용함으로 기업의 중요한 내부 정보 유출을 모니터링 및 차단에 목적이 있다.

• 한국초전도ㆍ저온공학회논문지
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• 제12권3호
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• pp.12-15
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• 2010

Important key technologies of high-$T_c$ superconducting (HTS) transformer may include the HTS wire technology, bushing technology, cooling technology, AC loss, reduction technology, large current technology, and cryogenic temperature insulation technology. From among others, the cryogenic temperature insulation technology may be specifically a core technology for ensuring reliability for the smaller size, stability, economic efficiency, and power supply of a transformer. Therefore, the electric insulation technology of a superconducting transformer should be prerequisite. Such relevant studies are ongoing, but still, they are very insufficient for establishing the cryogenic insulation technology as of yet. Therefore, this paper simulated HTS transformer applied with continuous transposed conductor (CTC), which has been studied as a way of reducing AC loss. Also, the paper analyzed the insulation configuration of HTS transformer and bushing, and, accordingly, reviewed various characteristics of insulation breakdown out of liquid nitrogen. Thus, the paper constituted insulation database, and it is going to design the insulation of a transmission class HTS transformer and bushing.

• 한국정밀공학회지
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• 제13권5호
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• pp.95-103
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• 1996

This paper describes a computer aided design system for spur and helical gears. To establish the appropriate program, an integrate approach based on a rule-base system was adopted. This system is implemented on the personal computer and its environment is a commercial CAD package called AutoCAD. This system includes a main program and five sub-modules such as data input module, tooth profile drawing module, strength calculation module, and drawing edit module. In the main program, all the sub-modules are loaded and the type of gear and tooth profile are selected. In the data input module, the variables which are necessary to the design of gear are selected from the database. In the drawing module, from the calculated results, the required gear tooth is produced on the screen. The developed system that aids gear designer provides powerful capabilities for gear design.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권3호
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• pp.794-815
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• 2023

The rapid development of mobile communication not only has made the industry gradually diversified, but also has enhanced the service quality requirements of users. In this regard, it is imperative to consider jointly network slicing and mobile edge computing. The former mainly ensures the requirements of varied vertical services preferably, and the latter solves the conflict between the user's own energy and harsh latency. At present, the integration of the two faces many challenges and need to carry out at different levels. The main target of the paper is to minimize the energy consumption of the system, and introduce a multi-slice joint task offloading and resource allocation scheme for massive multiple input multiple output enabled heterogeneous networks. The problem is formulated by collaborative optimizing offloading ratios, user association, transmission power and resource slicing, while being limited by the dissimilar latency and rate of multi-slice. To solve it, assign the optimal problem to two sub-problems of offloading decision and resource allocation, then solve them separately by exploiting the alternative optimization technique and Karush-Kuhn-Tucker conditions. Finally, a novel slices task offloading and resource allocation algorithm is proposed to get the offloading and resource allocation strategies. Numerous simulation results manifest that the proposed scheme has certain feasibility and effectiveness, and its performance is better than the other baseline scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권1호
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• pp.97-119
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• 2023

The number of industrial Internet of Things (IoT) users is increasing rapidly. Lightweight block ciphers have started to be used to protect the privacy of users. Hardware-oriented security design should fully consider the use of fewer hardware devices when the function is fully realized. Thus, this paper designs a lightweight block cipher IIoTBC for industrial IoT security. IIoTBC system structure is variable and flexibly adapts to nodes with different security requirements. This paper proposes a 4×4 S-box that achieves a good balance between area overhead and cryptographic properties. In addition, this paper proposes a preprocessing method for 4×4 S-box logic gate expressions, which makes it easier to obtain better area, running time, and power data in ASIC implementation. Applying it to 14 classic lightweight block cipher S-boxes, the results show that is feasible. A series of performance tests and security evaluations were performed on the IIoTBC. As shown by experiments and data comparisons, IIoTBC is compact and secure in industrial IoT sensor nodes. Finally, IIoTBC has been implemented on a temperature state acquisition platform to simulate encrypted transmission of temperature in an industrial environment.