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Reliable Fault Diagnosis Method Based on An Optimized Deep Belief Network for Gearbox
이철희,Oybek Eraliev,Ozodbek Xakimov,이철희 사단법인 유공압건설기계학회 2023 드라이브·컨트롤 Vol.20 No.4
High and intermittent loading cycles induce fatigue damage to transmission components, resulting in premature gearbox failure. To identify gearbox defects, numerous vibration-based diagnostics techniques, using several artificial intelligence (AI) algorithms, have recently been presented. In this paper, an optimized deep belief network (DBN) model for gearbox problem diagnosis was designed based on time-frequency visual pattern identification. To optimize the hyperparameters of the model, a particle swarm optimization (PSO) approach was integrated into the DBN. The proposed model was tested on two gearbox datasets: a wind turbine gearbox and an experimental gearbox. The optimized DBN model demonstrated strong and robust performance in classification accuracy. In addition, the accuracy of the generated datasets was compared using traditional ML and DL algorithms. Furthermore, the proposed model was evaluated on different partitions of the dataset. The results showed that, even with a small amount of sample data, the optimized DBN model achieved high accuracy in diagnosis
Design analysis and simulation of an external helical gear
이철희,양진룽,이강희,이철희 사단법인 유공압건설기계학회 2023 드라이브·컨트롤 Vol.20 No.4
This study optimized the parameters of the helical gear based on the original external meshing helical gear pump, combined with the analysis of the stability and flow of the basic parameters of the equipment; herringbone gears were used to eliminate the axial force generated by the helical gears. An optimized helical gear rotor was built with NX. The error between the simulation and calculation results of pump displacement was 3.95% and the simulation results were valid. Analysis of the outlet pressure and lift changes (maximum change rates of 0.38% and 0.25%), pressure analysis of the XY center plane at different times in the same cycle (no pressure surge or drop), and analysis of the axial force of the primary and driven rotors (axis The axial force is close to 0) were performed. The results showed that the flow pulsation of the external gear pump was slight, the operation was smooth, vibration and friction were reduced, the wear of bearings and other components could be diminished, and the service life of the equipment was extended. The simulation results showed that the external gear pump met the design requirements.
이철희,윤자복,이강수,이재서,민양기 대한비과학회 1997 Journal of rhinology Vol.4 No.2
Objectives:The aim of this study was to investigate whether the ciliary activity of respiratory epithelium is affected in allergicrhinitis. Methods:Twenty Wistar rats were divided into an unsensitized control group and sensitized allergic group. The sensitizedgroup was immunized intraperitoneally with ovalbumin, followed by intranasal administration of ovalbumin. Allergy wasdetermined by an increase in nasal symptoms, the number of tissue eosinophils and a positive result to a passive cutaneous anaphylaxis(PCA) test. Nasal, nasopharyneal, tracheal, and bronchial epithelial cells were obtained from both the control and allergicgroups. Ciliary beat frequency (CBF) was measured using a video-computerized analysis technique in vitro. We compared theCBF of two groups in each site. We also evaluated the findings of the nasal mucosa of both groups with an scanning electronmicroscope. Results:In vitro CBF measurement demonstrated that the CBF of the control and allergic groups did not differsignificantly (p>0.05). Conclusion:CBF is not affected by respiratory allergy.
남상영,정승근,김인재,김민자,이철희,김태수 韓國作物學會 2001 한국작물학회지 Vol.46 No.3
Source와 sink의 상대적 크기가 다른 고구마 품종간 이면접목을 통하여 생육에 미치는 고구마의 source와 sink의 상호관계를 분석함으로써, 고구마의 품종육성 및 재배법개선에 필요한 기초자료를 얻고자 수행한 결과를 요약하면 다음과 같다. 1 만장, 괴근수는 접목에 의하여 감소되었으며, 접목조합에 따라서 차이가 있었다. 2. 지상부의 생육은 접수, 지하부의 생육은 대목의 영향을 많이 받았다 3. 주만장과 괴근수에 대한 접목효과, 접수와 대목의 효과와 이들 간의 상호작용은 모두 유의성이 있었다. 4. 상저비율은 보통삽식>자가접목>이면접목 순으로 높았다. To obtain the basic information of high yielding ability for varietal improvement and cultural practice, reciprocal grafts were made analyzed among five sweet potato cultivars. Five cultivars were characterized with the different in whose source and sink capacities. Grafting decreased main vine length, number of tuberous roots per plant, but its effects were different among grafting combinations. The growth of vines was affected more by scion, while growth and yield of under-ground were influenced more by stock. Grafting effects, interactions between stock and scion for main vine length and number of tuberous roots were highly significant in diallel grafting. The percentage of marketable tuberous roots was higher in the order of stem cutting>self grafting>reciprocal grafting.
이철희,김동규,Chulhee Lee,Donggyou Kim 한국터널지하공간학회 2023 한국터널지하공간학회논문집 Vol.25 No.3
The purpose of this paper is to examine the most recent tunnel scanning systems to obtain insights for the development of non-contact mobile inspection system. Tunnel scanning systems are mostly being developed by adapting two main technologies, namely laser scanning and image scanning systems. Laser scanning system has the advantage of accurately recreating the geometric characteristics of tunnel linings from point cloud. On the other hand, image scanning system employs computer vision to effortlessly identify damage, such as fine cracks and leaks on the tunnel lining surface. The analysis suggests that image scanning system is more suitable for detecting damage on tunnel linings. A camera-based tunnel scanning system under development should include components such as lighting, data storage, power supply, and image-capturing controller synchronized with vehicle speed.
이철희 한국T.S.엘리엇학회 2014 T.S. 엘리엇 연구 Vol.24 No.2
엘리엇은 몇몇 낭만주의 시인들에 대하여 자신의 견해를 밝힌바 있다. 이 글은 엘리엇이 1937년에 작성한 「바이런」을 중심으로 엘리엇의 바이런에 대한 평가의 내용을 중심으로 살펴보았다. 엘리엇은 바이런의 생애는 비교적 설명이 되어 밝혀졌지만 그의 문학적 특징은 생애에 비해 설명되지 않았다며 그가 이 일을 수행하겠다고 주장한다. 그러면서 엘리엇은 우선 작품의 양과 질에 대한 관계로 관심을 돌리며 바이런의 경우 양적인 측면은 한계를 규정짓기가 난해하지만 질적인 측면은 우수하다고 한다. 그러나 시인으로서의 바이런의 경우, 단시는 물론 장시에 있어서도 바이런이 우수하다고 평가한다. 또한 바이런의 악마주의를 지목하며 엘리엇은 이것이 복합적 특성을 지니고 있다고 평가한다. 즉, 단순하게 정의할 수는 없다는 것이 엘리엇의 생각이다. 그리고 「바이런」의 대부분은 『돈 주안』에 대한 엘리엇의 평가로 구성되어 있다. 여기서 엘리엇은 바이런의 재담가로서의 훌륭함, 바이런이 창작한 플롯의 우수함, 설화시로서의 훌륭함, 표현 방식의 탁월성 등을 바이런의 장점으로 규정한다.