• Proceedings of the KWS Conference
• /
• 2009.11a
• /
• pp.83-83
• /
• 2009

The automotive chassis components are structural assemblies that support the engine, suspension, and steering components of the vehicle. For the development of AHSS components, the durability analysis is important. In this paper, the low cycle fatigue property of AHSS was evaluated for the geometry complex and local plasticity in the base material. The GMAW optimization was implemented for the weld soundness using the moving least square method. And the weld S-N curves of AHSS were evaluated to access durability analysis for the weld region. For the verification, the durability analysis of the couple torsion beam axle (CTBA) was performed and compared to the rig test result. The durability analysis using the low cycle fatigue property and the evaluated weld S-N curve of AHSS met the good agreement with the test result.

• Tribology and Lubricants
• /
• v.18 no.2
• /
• pp.117-126
• /
• 2002

Abstract - An integrated condition monitoring algorithm based on an expert system was implemented in this work in order to monitor effectively the machine conditions. The knowledge base was consisted of numeric data which meant the posterior probability of each measurement parameter for the representative machine failures. Also the inference engine was constructed as a series of statistical process, where the probable machine fault was inferred by a mapping technology of pattern recognition. The proposed algorithm was, through the user interface, applied for an air compressor system where the temperature, vibration and wear properties were measured simultaneously. The result of the case study was found fairly satisfactory in the diagnosis of the machine condition since the predicted result was well correlated to the machine fault occurred.

• Proceedings of the KWS Conference
• /
• 2005.11a
• /
• pp.168-170
• /
• 2005

Nickel base brazes containing boron and silicon as melting point depressants are used extensively in the joining and repair of hot-section components in next generation nuclear reactor and aero-engine. Therefore, the present study has investigated the preliminary applicability of nickel based alloying nano powders. Nano Ni-based alloying powders synthesized by Pulsed Wire Evaporation (PWE) method. It's powder morphology and phase transformation temperature were analyzed by scanning electron microscopy, transmission electron microscopy, and differential scanning calorimeter(DSC). The powder particle size was approximately 10${\sim}$100nm and exhibits a quite even equiaxed shape. The results of DSC measurement show that both the nano Inconel 625 nano powder and Inconel 718 nano powder presents similar liquidus temperatures approximately $1373^{\circ}C$ and $1380^{\circ}C$ respectively.

• Proceedings of the KIEE Conference
• /
• 2001.11b
• /
• pp.374-376
• /
• 2001

In this paper, we developed the fault diagnostic expert system of silicone-immersed transformer using dissolved gas analysis. The knowledge base module consists of the knowledge using the rule: if Then . The inference engine uses the fuzzy rule for the management of uncertainty of the boundary and rule and derivate the Belief and Plausibility of the normality and fault using Dempster-Shafer theory. The expert system is connected to the database and it can manages the history of gas-data of the transformer.

• Journal of Power System Engineering
• /
• v.11 no.1
• /
• pp.28-32
• /
• 2007

This research proposed that development of wireless condition monitoring system using WLAN network. It offers the prospect of improved performance that removed a current a coaxial cable and reduced overall cost of condition monitoring. Recently, there is an interesting concern for wireless system as an infrastructure technology construct ubiquitous computing environment in the future. High performance computing board makes minimization with integrate of a various functions which support wireless LAN network. Instead of wired coaxial cable using measurement system in industry, wireless LAN network assists industry automation and engineer's convenience. Developed system adapted wireless LAN network on shipboard with engine room and deck house, it also executes wireless measurement test on 8500TEU containership.

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.04b
• /
• pp.160-162
• /
• 2002

SNP는 개인과 개인간의 DNA에 존재하는 한 염기 쌍의 차이(single base-pair variation)이다. SNP를 이용하면 사람마다 다른 유전병의 형태 등을 규명할 수 있다. 본 논문에서는 한국생명공학연구원의 유전체 사업단에서 개발해 오고 있는 웹기반 SNP데이터 검색 시스템의 설계와 구현에 대해서 설명한다. 본 시스템은 일반 속성(attribute)을 저장하고 검색하기 위해 PostgreSQL DBMS를 사용하고, DNA 시퀸스 검색을 위해 BLAST검색엔진을 사용한 약결합 아키텍쳐(loosely-coupled architecture)를 채택하고 있다. 즉, 일반 속성으로 저장될 수 있는 데이터들은 데이터베이스의 테이블들의 컬럼 값으로 저장하고 SQL 언어를 통해 검색할 수 있도록 하였으며, DNA 시퀸스 검색을 위해서는 BLAST에서 제공하는 인덱스를 구축하고 BLAST 명령어를 사용하여 검색할 수 있도록 하였다. 또한, 결과 분석 모듈을 구현하여 검색 결과들이 다른 웹 사이트의 데이터를 가리키도록 하였다.

• 유공압시스템학회:학술대회논문집
• /
• 2010.06a
• /
• pp.25-32
• /
• 2010

A geortor type pump is widely used in lubrication and actuator systems. Especially the pump is an essential machine element of an automotive engine to feed lubrication oil and power source of automatic transmission. A gerotor is a planar mechanism consist of a pair of rotor and circular tooth of stator assembly which forms a closed space. However, related industries do not have necessary technology to design and optimize the pump and paid royalties of gerotor profile on an advanced company. Also, gerotor profiles with setting design parameter have not been sufficiently analyzed from a theoretical view. Therefore, it is very difficult for designer to decide the specifications of the gerotor profiles, and calculation and fluctuation of flow rate is not yet confirmed. In this study, theoretical analyses and optimal design of the gerotor profiles have been performed numerical method by mathematical base. An automated design system of the tooth profile has been developed through MATLAB GUI Program considering various design parameters.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.1
• /
• pp.66-73
• /
• 2004

This paper presents characteristics of combustion and exhaust gas properties according to variation of the combustion chamber for economy and emissions standards. In order to use combustion and exhaust gas properties data, it is necessary to build some data base, which use cylinder pressure sensor and emission tester. A feasibility and necessity of combustion pressure based cylinder spark timing control has been examined. So, this was obtained the coefficient of variation(COV) and the specific fuel consumption(sfc). Using the results of the test, the effects of the variable combustion chamber can be improved combustion stability and be reduced exhaust emission.

• Journal of the Korean Society for Heat Treatment
• /
• v.8 no.1
• /
• pp.24-31
• /
• 1995

Heat flow equation and FEM have been used to calculate the hardening section of material in laser transformation hardening. SCM440 used as the diesel engine piston of vessel has been hardened by a $CO_2$ laser with the wavelength of $10.6{\mu}m$. The specimens were inclined from 0 to 70 degree to investigate the characteristics of laser hardening. The geometrical factor of heat flow equation affects the size of hardening area. The case width decreased with increasing travel speed and the case width increased with increasing inclined angle. Maximum case depth was achieved about 1.0mm and maximum hardness of laser hardened area was of 2.8 times than that of base metal. Experimental data show good agreement with the theoretical calculations for given laser hardening conditions.

• Journal of the Semiconductor & Display Technology
• /
• v.21 no.3
• /
• pp.7-11
• /
• 2022

Object detection technology is one of the main research topics in the field of computer vision and has established itself as an essential base technology for implementing various vision systems. Recent DNN (Deep Neural Networks)-based algorithms achieve much higher recognition accuracy than traditional algorithms. However, it is well-known that the DNN model inference operation requires a relatively high computational power. In this paper, we analyze the inference time complexity of the state-of-the-art object detection architecture Yolov7 in various environments. Specifically, we compare and analyze the time complexity of four types of the Yolov7 model, YOLOv7-tiny, YOLOv7, YOLOv7-X, and YOLOv7-E6 when performing inference operations using CPU and GPU. Furthermore, we analyze the time complexity variation when inferring the same models using the Pytorch framework and the Onnxruntime engine.