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Breakdown Characteristics and Lifetime Estimation of Rubber Insulating Gloves Using Statistical Models

  • Kim, Doo Hyun;Kang, Dong Kyu
    • International Journal of Safety
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    • v.1 no.1
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    • pp.36-42
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    • 2002
  • This paper is aimed at predicting the life of rubber insulating gloves under normal operating stresses from relatively rapid test performed at higher stresses. Specimens of rubber insulating gloves are subject to multiple stress conditions, i.e. combined electrical and thermal stresses. Two modes of electrical stress, step voltage stress and constant voltage stress are used in specimen aging. There are two types of test for electrical stress in this experiment: the one is Breakdown Voltage (BDV) test under step voltage stress and thermal stress and the other is lifetime test under constant voltage stress and temperature stress. The ac breakdown voltage defined as the break-down point of insulation that leakage current excesses a limit value, l0mA in this experiment, is determined. Because the very high variability of aging data requires the application of statistical model, Weibull distribution is used to represent the failure times as the straight line on Weibull probability paper. Weibull parameters are deter-mined by three statistical methods i.e. maximum likelihood method, graphical method and least squares method, which employ SAS package, Weibull probability paper and FORTRAN, respectively. Two chosen models for predicting the life under simultaneous electrical and thermal stresses are inverse power model and exponential model. And the constants of life equation for multistress aging are calculated using numerical method, such as Gauss Jordan method etc.. The completion of life equation enables to estimate the life at normal stress based on the data collected from accelerated aging test. Also the comparison of the calculated lifetimes between the inverse power model and the exponential model is carried out. And the lifetimes calculated by three statistical methods with lower voltage than test voltage are compared. The results obtained from the suggested experimental method are presented and discussed.

Incorporating Genetic Operators into Optimizing Highway Alignments (도로선형최적화를 위한 유전자 연산자의 적용)

  • Kim, Eung-Cheol
    • Journal of Korean Society of Transportation
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    • v.22 no.2 s.73
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    • pp.43-54
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    • 2004
  • This study analyzes characteristics and applicability of genetic algorithms and genetic operators to optimize highway alignments. Genetic algorithms, one of artificial intelligence techniques, are fast and efficient search algorithms for generating, evaluation and finding optimal highway alignment alternatives. The performance of genetic algorithms as an optimal search tool highly depends on genetic operators that are designed as a problem-specific. This study adopts low mutation operators(uniform mutation operator, straight mutation operator, non-uniform mutation operator whole non-uniform mutation operator) to explore whole search spaces, and four crossover operators(simple crossover operator, two-point crossover operator, arithmetic crossover operator, heuristic crossover operator) to exploit food characteristics of the best chromosome in previous generations. A case study and a sensitivity analysis have shown that the eight problem-specific operators developed for optimizing highway alignments enhance the search performance of genetic algorithms, and find good solutions(highway alignment alternatives). It has been also found that a mixed and well-combined use of mutation and crossover operators is very important to balance between pre-matured solutions when employing more crossover operators and more computation time when adopting more mutation operators.

A Study on the Innovation of Course Contents and Instruction of Basic Design in Interior Design Education (실내디자인 교육에서의 기초디자인의 교육내용 및 교육방법 개선에 관한 연구)

  • Han, Young-Ho;Kim, Dong-Young
    • Korean Institute of Interior Design Journal
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    • no.3
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    • pp.46-57
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    • 1994
  • Today, it is a fact that interior design plays a very important role as much as architecture on contributing to our society as a rising new professional field. On the other hand, our interior design education is still in immagture stage unlike the graudal development of the mood of interior design line , If the interior design field has any educational value to invest to be noticed as an environmental design that creates the human environment. There are great deal of meanings to indicate the direction for better education after recognizing the manu different problems on presently offering interior design education. Therefore, the objectives of this study is , after establishing the innovative methods of education and course contents of the four year interior design program, to produce the interior designers of manifold abilities, who is able to fit well in the professional practice, in order to materialize the settlement of interior design education which will be the key point in our circumstances, which has ow social recognition toward interior design. There were four phases in this study. First was to gather and to analyze information from printed materials, such as curriculum and catalog from each institution. Secondly, we had collected existing previous studies in all interior design area in order to sude as references. Thirdly, we have managed to suggest ideal improvement for better basic design program in the area of interior design education after the arranging and analyzing . Finally, we were able to persuade the importance of improved basic design program to the interior design education parties and to suggest the direction for the future. Because interior design as a scholastic pursuit is combined practical application study by the art and technology, it emphasizes specialty . From that reason interior design education must be performed as professional specialist education instead of vocational education. In another words, the ultimate goal of the interior design objectives must be in producing professional specialist.

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Real-time Calculation of Geoid Applicable to Embedded Systems (내장형 시스템에 적용 가능한 지오이드의 실시간 결정)

  • Kim, Hyun-seok;Park, Chan-sik
    • Journal of Advanced Navigation Technology
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    • v.24 no.5
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    • pp.374-381
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    • 2020
  • In order to improve the vertical position accuracy, the advantages of GPS and barometric altimeter are combined and used, but in order to fuse the two sensors, the geoid altitude must be compensated. In this paper, we proposed a technique that can calculate geoid altitude in real time even in low-cost embedded systems applied to drones or autonomous vehicles. Since the reference EGM08 is determined by a polynomial of the 2160th order, real-time calculation is impossible in the embedded system. Therefore, by introducing a linear interpolation technique, the amount of calculation was increased, and the storage space was saved by 75% by using the integer geoid height as a grid point. The accuracy of the proposed technique was evaluated through simulation, and it was confirmed that the accuracy of the maximum error is -1.215 m even in the region where the geoid change is rapid.

Improved Survival of Cervical Cancer Patients in a Screened Population in Rural India

  • Jayant, Kasturi;Sankaranarayanan, Rengaswamy;Thorat, Ranjit V;Muwonge, Richard;Hingmire, Sanjay J;Panse, Nandkumar S;Shastri, Surendra S;Malvi, Sylla G;Nene, Bhagwan
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.11
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    • pp.4837-4844
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    • 2016
  • Objectives: To describe the survival experience of cervix cancer patients in a screened rural population in India. Methods: Included 558 cervical cancer patients diagnosed in 2000-2013 in a cohort of 100,258 women invited for screening during 2000-2003. The primary end point was death from cervical cancer. We used the Kaplan-Meier method to estimate cumulative observed survival and Cox proportional hazards regression to assess the effect of patient characteristics on survival after diagnosis. Results: Of the 558 cases included, 143 (26%) and 114 (20%) were diagnosed in stages IA and IB respectively; 252 (45.2%) were dead, and 306 (54.8%) were alive at the last follow-up. The overall 5-year observed survival was 60.5%. The 5-year survival of stage IA patients was 95.1% and 5.3% for stage IV patients. All surgically treated stage IA patients, 94.1% of stage IB patients receiving intracavitary radiotherapy, 62% of stage IIB, 49% of stage III and 25% of stage IV patients receiving radiotherapy survived for 5 years. Conclusion: Higher 5-year survival in our study than elsewhere in India is due to the high proportion of early stage cancers detected by screening combined with adequate treatment, resulting into a favourable prognosis.

A study of the tendency of anti-cancer experimental study using herbal medicines (한약(韓藥)을 이용(利用)한 항암(抗癌) 실험연구(實驗硏究)의 경향(傾向)에 관(關)한 고찰(考察))

  • Kim, Hyung-A;Lim, Sung-Woo;Lee, Won-Chul
    • THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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    • v.4 no.1
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    • pp.211-232
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    • 1998
  • Because there were lots of side effects and tolerances to the existing anticancer therapeutics, the experiment extracting the anticancer effect from medicinal herbs is in progress liviely. Therefore the purpose of this study were to research the tendency and the course of anticancer studies. To research the tendency of anticancer studies, medicinal herbs of fifty three experimental papers were analyzed and to examine the course of studies, anticancer papers in the medical world were used. The obtained results were as follows: Methods of herbal medicinal treatments were elimination the pathogenic factor(祛邪) and supporting healthy energy(扶正) method used. In this study, immediately tumor bearing and immune response were the most important point. The subject of immediately tumor bearing was not in the specific cancer but in the influence on the life span of general cencerous cells. In the experimental study of immune response, the effect on NK cell activity of medicinal herbs most studied. The combined usage of medicinal herbs and anticancer agent mostly intended to know whether it inhibits the tumor cell growth. The serum test and blood cell number test show if medicinal herbs inhibit side effect of anticancer agent. More than 80 percents of used medicinal herbs, there were anticancer activities. However anticancer experimental studies using medicinal herbs two weak points. The one, it was difficult to choose a prescription according to differentiation of symptoms and signs(辨證論) of the Oriental Medicine, because we put to the test not a man but a mouse. The other, as we observed the indirect effect of the whole physiological regulation caused by synergic effects of the complex prescription, we don't understand the detailed mechanism of the herb. Therefore, if the anticancer effect of the herb is proved the experiment, we should research the concrete medical action of medicinal herbs and immunological analysis of herbal medicines to the body.

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Proposed surface modeling for slip resistance of the shoe-floor interface

  • Kim, In-Ju
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1995.04a
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    • pp.515-528
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    • 1995
  • Slips and falls are the major causes of the pedestrian injuries in the industry and the general community throughout the world. With the awareness of these problems, the friction coefficients of the interface between floorings and footwear have been measured for the evaluation of slip resistant properties. During this measurement process, the surface texture has been shown to be substantially effective to the friction mechanism between shoe heels and floor surfaces under various types of walking environment. Roughness, either of the floor surface or shoe heels, provides the necessary drainage spaces. This roughness can be designed into the shoe heel but this is inadequate in some cases, especially a wear. Therefore, it is essential that the proper roughness for the floor surface coverings should be provided. The phenomena that observed at the interface between a sliding elastomer and a rigid contaminated floor surface are very diverse and combined mechanisms. Besides, the real surface geometry is quite complicate and the characteristics of both mating surfaces are continuously changing in the process of running-in so that a finite number of surface parameters can not provide a proper description of the complex and peculiar shoe - floor contact sliding mechanism. It is hypothesised that the interface topography changes are mainly occurred in the shoe heel surfaces, because the general property of the shoe is soft in the face of hardness compared with the floor materials This point can be idealized as sliding of a soft shoe heel over an array of wedge-shaped hard asperities of floor surface. Therefore, it is considered that a modelling for shoe - floor contact sliding mechanism is mainly depended upon the surface topography of the floor counterforce. With the model development, several surface parameters were measured and tested to choose the best describing surface parameters. As the result, the asperity peak density (APD) of the floor surface was developed as one of the best describing parameters to explain the ambiguous shoe - floor interface friction mechanism. It is concluded that the floor surface should be continuously monitored with the suitable surface parameters and kept the proper level of roughness to maintain the footwear slip resistance. This result can be applied to the initial stage of design for the floor coverings.

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Robust Face Recognition System using AAM and Gabor Feature Vectors (AAM과 가버 특징 벡터를 이용한 강인한 얼굴 인식 시스템)

  • Kim, Sang-Hoon;Jung, Sou-Hwan;Jeon, Seoung-Seon;Kim, Jae-Min;Cho, Seong-Won;Chung, Sun-Tae
    • The Journal of the Korea Contents Association
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    • v.7 no.2
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    • pp.1-10
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    • 2007
  • In this paper, we propose a face recognition system using AAM and Gabor feature vectors. EBGM, which is prominent among face recognition algorithms employing Gabor feature vectors, requires localization of facial feature points where Gabor feature vectors are extracted. However, localization of facial feature points employed in EBGM is based on Gator jet similarity and is sensitive to initial points. Wrong localization of facial feature points affects face recognition rate. AAM is known to be successfully applied to localization of facial feature points. In this paper, we propose a facial feature point localization method which first roughly estimate facial feature points using AAM and refine facial feature points using Gabor jet similarity-based localization method with initial points set by the facial feature points estimated from AAM, and propose a face recognition system based on the proposed localization method. It is verified through experiments that the proposed face recognition system using the combined localization performs better than the conventional face recognition system using the Gabor similarity-based localization only like EBGM.

A Study on the Deployment of a Sea Based Sensor Platform for the Detection of a SLBM (잠수함 발사 탄도미사일 탐지를 위한 해상 센서플랫폼의 배치에 관한 연구)

  • Kim, Jiwon;Kwon, Yong Soo;Kim, Namgi;Kim, Dong Min;Park, Young Han
    • Journal of Advanced Navigation Technology
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    • v.19 no.5
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    • pp.363-369
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    • 2015
  • This paper describes deployment of a sea based sensor platform for the detection of a submarine launched ballistic missile (SLBM). Recently, North Korea successfully conducted the underwater launching test of the SLBM, which will seriously threaten the global security. To defend these threats successfully, a sensor platform of the ballistic missile defense (BMD) should be deployed in the area of high detection probability of the missile. The maximum detection range characteristics of the typical radar sensor system, however, depend on the radar cross section (RCS) and flight trajectories of the target. In this point of view, this work analyzed the flight trajectories based on the tactics and calculated the RCS of the SLBM. In addition, sea based sensor platform position is proposed from the analysis of the detection time.

A Secure WPA-PSK Protocol Resistant to Dictionary Attack on Smartphone Communication Using Wi-Fi Channel (Wi-Fi를 이용한 스마트폰에서 사전 공격에 안전한 WPA-PSK 프로토콜)

  • Park, Geun-Duk;Park, Jeong-Soo;Ha, Jae-Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.4
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    • pp.1839-1848
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    • 2012
  • Recently, smartphone communications using Wi-Fi channel are increasing rapidly to provide diverse internet services. The WPA security protocol was used for data protection between user and wireless AP. However, WPA-PSK protocol was known to be weak to the dictionary attack. In this paper, we proposed a secure WPA-PSK protocol to resist the dictionary attack. Since the proposed method was designed to generate a strong encryption key which is combined the Diffie-Hellman key agreement scheme with secrecy property of PSK(Pre-Shared Key), we can protect the Wi-Fi channel from Man-In-The-Middle attack and Rogue AP impersonation attack.