• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.132-137
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• 2004

On-Board Diagnostic(OBD) systems are in most cars and light trucks on the load today. During the 1970's and early 1980's manufacturers started using electronic means to control engine functions and diagnose engine problems. The CARB's diagnostic requirements to meet EPA emission standards have been designated as OBD with a goal of monitoring all of the emissions-related components, as well as the chassis, body, accessory devices and the diagnostic control network of the vehicle for proper operation. In this paper, we present a remote measurement system for the wireless monitoring of diagnosis signal and sensors output signals of ECU adopted KWP2000, united the OBD communication protocol, on OBD-compliant vehicle using the wirless communication technique of Bluetooth. In order to measure the ECU signals, the interface circuit is designed to communicate ECU and designed terminal wirelessly according to the ISO, SAE regulation of communication protocol standard. A microprocessor S3C3410X is used for communicating ECU signals. The embedded system's software is programmed to measure the ECU signals using the ARM compiler and ANCI C based on MicroC/OS kernel to communicate between bluetooth modules using bluetooth stack. The diagnostic system is developed using Visual C++ MFC and protocol stack of bluetooth for Windows environment. The self-diagnosis and sensor output signals of ECU is able to monitor using PC with bluetooth board connected in serial port of PC. The algorithms for measuring the ECU sensor output and self-diagnostic signals are verified to monitor ECU state. At the same time, the information to fix the vehicle's problem can be shown on the developed monitoring software. The possibility for remote measurement of self-diagnosis and sensor signals of ECU adopted KWP2000 in embedded system verified through the developed systems and algorithms.

• 대한기계학회논문집
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• 제15권6호
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• pp.2026-2036
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• 1991

본 연구에서는 동력전달용 치차설계 전문가 시스템을 구축하기 위한 일단의 연구로서 먼저, 치차의 시험중 또는 사용중에 일어나는 파손에 대하여 파손의 원인탐 색과 대책수립을 위한 전문가 시스템을 개발한다.

• 대한전기학회논문지:전력기술부문A
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• 제54권5호
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• pp.205-211
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• 2005

Recently, power system is getting larger and more complex. When the complex power system has a problem, it is very difficult even for the experts to find out where the problem is and to make a timely decision by operators. There have been many studies on these problems but the results are not good enough for applying to real power system. Therefore, power system operators always had to judge the exact state of power system and be preparative for the problems that can occur later. We developed new methods that can be applied to complex power system by dividing the system into small modules. By using 'module', we can combine small modules together to make complex power systems and the knowledge base that is applied to fault diagnosis system. As a result, compared to previously developed diagnosis products, operation time is shortened and the knowledge base is become simpler and clearer, which made online usage capable. This system can be used as a complementary measurement that helps the operator from making any mistakes.

• 한국항해항만학회지
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• 제33권10호
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• pp.671-678
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• 2009

현재 진동 정보를 통해 기계 설비의 상태나 고장 유무를 판단하는 연구들이 다수 진행 중에 있는데, 대부분의 연구에서는 설비에 대한 진동을 모니터링하거나 고장 유무를 판별하여 사용자에게 알리는 수준이다. 본 논문에서는 진동 정보 적용 대상을 선박으로 정하고, 진동에 의한 고장 진단과 판별을 보다 정교하게 수행하는 선박 엔진 감지 기법과 시스템을 제안하였다. 일차적으로 이중화된 진동 정보 판별 기법을 적용하여 진동 정보를 확인한 다음에 고장 유무를 검사한다. 만일 고장이 발생한 경우에는 적분을 이용하여 고장 진동 파형에 대한 넓이를 기준으로 어떤 유형의 고장인지를 판별할 수 있는 기법을 적용하였다. 또한 선박의 진동 경향 분석과 엔진 안전 보존을 목적으로 진동 정보를 데이터베이스에 저장하고 추적할 수 있도록 시스템을 구현하였다. 제안 시스템을 선박 엔진의 고장 판별 유무와 고장 진동 파형 감별 인자에 대해 실험을 수행한 결과 고장 판별은 약 98% 정확성을 가졌고 고장 진동 파형 감별에서는 약 72% 정확성을 가졌다.

• 대한예방한의학회지
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• 제20권1호
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• pp.75-87
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• 2016

Objectives : This study aims to classify and analyze literature related to moire topography, as a diagnostic device of Korean medicine, discuss research trends and major results, and demonstrate the value of moire topography. Methods : To investigate moire topography research trends, Korean keywords that signify 'moire' were searched in a Korean journal search engine. Initially, 2,988 papers were found in the research, and, after classifying them and removing those that are duplicate in other databases, only 37 papers were applicable for the literature review in this study. To analyze research trends, the 37 papers were analyzed based on the publication year, research field, journal, and research type, and, clinical articles were classified based on the diagnosis purpose, subject characteristics, diagnosis method, test method, and test result, for analysis. Results : Moire topography research in South Korea was first conducted in 1995 and most active in 2003, mostly in the field of Korean medicine. In the journal analysis, The Journal of Korea CHUNA Manual Medicine for Spine & Nerves published the highest number of papers, most of which were clinical articles and the rest were literature review. And, in the analysis of clinical papers, based on the diagnosis purpose, muscle somatotype measurement was most common, followed by diagnosis of scoliosis. In terms of subjects, most studies focused on elementary, middle, and high school students, and, in terms of the diagnosis method, other tests were used in most studies. The analysis of moire topography methods showed that most studies measured the shoulder, back, and hip, and the most common measurement method in the studies measured the difference in contour lines on the left and right by designating a central line of the body. In terms of the result, most moire topography brought about significant diagnosis results, and many studies demonstrated its use for musculoskeletal diseases in particular. Conclusions : Moire topography is believed to be highly significant for diagnosis and treatment of musculoskeletal diseases and further research will be needed to support it.

• 한국항공우주학회지
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• 제32권3호
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• pp.51-57
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• 2004

본 연구에서는 신경회로망을 이용한 가스터빈 엔진의 지능형 성능 진단 컴퓨터 프로그램을 개발하였다. 최근에는 엔진 손상을 분석하는데 있어서 주요 구성품의 가스 경로를 실시간 모니터링(monitoring)하는 가스경로해석 (GPA, Gas Path Analysis)방법이 사용되고 있다. 그러나 엔진손상의 형태나 정도가 다양하고 복잡하기 때문에 가스경로해석 접근법만 가지고서는 엔진의 손상상태를 모두 모니터링하기란 쉽지 않다. 따라서 이 문제를 해결하기 위해 학습과 진단을 할 수 있는 신경회로망을 적용하였다. 본 연구에서는 PT6A-62 터보프롭 엔진의 진단에 1개의 은닉층을 갖는 역전파 신경회로망(BPN, Back Propagation Neural Network)이 제안되었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.187-194
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• 2008

Because the types and severities of most engine faults are various and complex, it is not easy that the conventional model based fault detection approach like the GPA(Gas Path Analysis) method can monitor all engine fault conditions. Therefore this study proposed newly a diagnostic algorithm for isolating and diagnosing effectively the faulted components of the smart UAV propulsion system, which has been developed by KARI(Korea Aerospace Research Institute), using the fuzzy logic and the neural network algorithms. A precise performance model should be needed to perform the model-based diagnostics. The based engine performance model was developed using SIMULINK. For the work and mass flow matching between components of the steady-state simulation, the state-flow library was applied. The proposed steady-state performance model can simulate off-design point performance at various flight conditions and part loads, and in order to evaluate the steady-state performance model their simulation results were compared with manufacturer's performance deck data. According to comparison results, it was confirm that the steady-state model well agreed with the deck data within 3% in all flight envelop. The diagnosis procedure of the proposed diagnostic system has the following steps. Firstly after obtaining database of fault patterns through performance simulation, then secondly the diagnostic system was trained by the FFBP networks. Thirdly after analyzing the trend of the measuring parameters due to fault patterns, then fourthly faulted components were isolated using the fuzzy logic. Finally magnitudes of the detected faults were obtained by the trained neural networks. Because the detected faults have almost same as degradation values of the implanted fault pattern, it was confirmed that the proposed diagnostic system can detect well the engine faults.

• 대한조선학회논문집
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• 제60권2호
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• pp.95-109
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• 2023

In the 4th industrial revolution, changes in the technological paradigm have had a direct impact on the maintenance system of ships. The 2-stroke low speed engine system integrates with the core equipment required for propulsive power. The Condition Based Management (CBM) is defined as a technology that predictive maintenance methods in existing calender-based or running time based maintenance systems by monitoring the condition of machinery and diagnosis/prognosis failures. In this study, we have established a framework for CBM technology development on our own, and are engaged in engineering-based failure analysis, data development and management, data feature analysis and pre-processing, and verified the reliability of failure mode DB using LSTM algorithms. We developed various simulated failure mode scenarios for 2-stroke low speed engine and researched to produce data on onshore basis test_beds. The analysis and pre-processing of normal and abnormal status data acquired through failure mode simulation experiment used various Exploratory Data Analysis (EDA) techniques to feature extract not only data on the performance and efficiency of 2-stroke low speed engine but also key feature data using multivariate statistical analysis. In addition, by developing an LSTM classification algorithm, we tried to verify the reliability of various failure mode data with time-series characteristics.

• Tribology and Lubricants
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• 제30권1호
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• pp.21-28
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• 2014

Damage to the cylinder liner of large ship engines, such as scuffing on the surface, can occur very easily because it is operated in a corrosive environment. This scuffing may be due to oil film destruction and corrosive wear caused by water and sulfur included in the fuel, abrasive impurities, and poor lubricants. Thus, a method for monitoring the condition and diagnosing the failure of the cylinder liner and piston ring is needed. In this study, a reciprocating friction and wear test was carried out with a cast iron specimen, which simulated an engine cylinder in a corrosive atmosphere. The lubricants used were base oil, stirred oil with distilled water, a NaCl solution, and dilute sulfuric acid. The friction coefficient and frequency spectrum were measured using a load cell and acceleration sense in each experimental condition. We then used these results to diagnose the failure of the cylinder liner.

• 한국생산제조학회지
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• 제24권2호
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• pp.203-210
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• 2015

This paper investigates the failure of a car with a 2.5-liter CRDi engine of the Hyundai Company. The failure is caused by intermittent poor acceleration while driving. To analyze the cause, we investigated the air intake volume, the fuel injection, and the air-fuel ratio, which were determined to be normal. The brake switch signal error was discovered while analyzing the function that limits the output of the engine. While investigating the cause, we discovered the corrosion of the pins on the connector of the brake switch. We determined that it was generated by soapy water flowing in the solar film. Therefore, the cause of the failure was the brake switch signal errors. Additionally, we determined that ECM was the normal fail-safe mode that implemented the override device for safety during normal acceleration. Based on these results, further solar film experiments must be conducted to fully elucidate the causes.