• Title/Summary/Keyword: Vector Field

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Magnetic Shielding with Thin Magnetic Materials near Power Cables (박판 자성 재료를 이용한 전력 케이블 인근의 자기장 차폐)

  • Kim, Sang-Beom;Soh, Joon-Young;Shin, Koo-Yong;Jeong, Jin-Hye;Myung, Sung-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.7
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    • pp.639-647
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    • 2009
  • In this work, wrapping conductors with thin magnetic materials is proposed as a magnetic shielding method. The 0.1 mm thick metal sheets of mu-metal, grain-oriented electrical steel, and non-oriented electrical steel were produced from commercial alloy sheets through cold rolling and followed high temperature annealing. In case of 3-phase electric currents, mu-metal was the best in shielding performance at a B-field magnitude of about 100 ${\mu}T$, whereas silicon steels were better than mu-metal at a B-magnitude over 500 ${\mu}T$. In addition, wrapping with silicon steel(inner) together with mu-metal(outer) resulted in a shielding factor less than 0.1 even at 500 ${\mu}T$. These results are due to changes in hierarchy of magnetic permeabilities of the materials with increasing magnetic field strength. In case of single-phase electric current, B-magnitude outside the magnetic shell was rather increased compared to the unshielded case. This result is explained by vector composition of B-fields near magnetic shielding materials.

Visual Interpretation about the Underground Information using Borehole Camera (휴대용 시추공 카메라를 이용한 지하정보의 가시화 기법)

  • Matsui Kikuo;Jeong Yun-Young
    • Tunnel and Underground Space
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    • v.15 no.1 s.54
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    • pp.28-38
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    • 2005
  • According to the recent development of measurement system utilizing one or a set of boreholes, visualization of the explored underground became to be a major issue. It induced even the introduction of monitoring apparatuses on the borehole wall with multi-function tool, but the usage of these was often limited by where is unfavorable rock condition and a few of engineers can approach. And so, a portable type of borehole camera with only the essential function has been investigated and a few of commercial models about this is recently being applied into the field condition. This paper was based on the monitoring results obtained using a commercial model by Dr. Nakagawa. Discontinuities in rock mass were the topic for the visualization, and it was studied how can visualize their three dimensional distribution and what a numerical formulation is needed and how to understand the visualization result. The numerical formulation was based on the geometric correlation between the dip direction / dip of discontinuous plane and the trend / plunge of borehole, a set of the equation of a plane was induced. As field application of this into two places, it is found that the above visualization methodology will be especially an useful geotechlical tool for analyzing the local distribution of discontinuities.

Epidemiological Observation on the Current Epidemic of Human Trypanosomiasis in Uganda (우간다의 Human Trypanosomiasis 대유행(大流行)에 관한 역학적(疫學的) 관찰(觀察))

  • Chu, He-Len;Rim, Hang-Jong;Chu, I.H.;Ongom, V.L.
    • Journal of agricultural medicine and community health
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    • v.5 no.1
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    • pp.5-15
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    • 1980
  • The first recorded trypanosomiasis epidemic in Uganda took place at the beginning of this century in the islands and in a strip along the northern shores of Lake Victoria, which resulted in deaths of 1/3 million people. The disease was partly controlled by early 1930's and continued to occur sporadically in certain localized foci. The disease has however flared up in an explosive outbreak in Busoga district along Lake Victoria since 1977. The incidence of disease in northern district adjacent to Southern Sudan is also increasing lately. This paper describes the three month observation on the surveillance and control activities in the epidemic areas and of various health units including the Vector Control Division, the Tsetse fly Control Division, Tororo Trypanosomiasis Research Institute, medical units in Busoga, and Acholi districts. Data analysis and review were made of disease information so far collected by various health units in the Ministry of Health and district health offices. The findings may be summarized in the following: 1) A total of 12, 100 patients and 38 deaths: have occured in Busoga district since 1977 onward, and over 100 cases of diseases arc occuring in the Northern region bordering Southern Sudan. 2) the distribution of trypanosomiasis is characterized with two district patterns. The disease caused by Trypanosoma rhodesiense occurs in Busoga and is transmitted by Glossina palpalis, G. fuscipes infested in the islands and in the northern shore of forests of Lake Victoria. Another type caused by Trypanosoma gambiense occurs in Madi and Acholi in the north and is transmitted by Glossina morsitans in Savannah. 3) The house survey in Rusoga indicated that most of patients keep domestic animals in their house premises, and are engaging in either farming or fishing. Practically all the patients remembered that they had been bitten by tsetse in the field. 4) The routine diagnostic methods in the hospital laboratory is carried out through the microscopic examination of trypanosome with Giemsa stain of blood and cerebro-spinal fluid, The measurement of ESR and IgM has been used by Tororo Tryponosomiasis Research Institute for field screening.

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Instructions and Data Prefetch Mechanism using Displacement History Buffer (변위 히스토리 버퍼를 이용한 명령어 및 데이터 프리페치 기법)

  • Jeong, Yong Su;Kim, JinHyuk;Cho, Tae Hwan;Choi, SangBang
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.10
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    • pp.82-94
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    • 2015
  • In this paper, we propose hardware prefetch mechanism with an efficient cache replacement policy by giving priority to the trigger block in which a spatial region and producing a spatial region by using the displacement field. It could be taken into account the sequence of the program since a history is based on the trigger block of history record, and it could be quickly prefetching the instructions or data address by adding a stored value to the trigger address and displacement field since a history is stored as a displacement value. Also, we proposed a method of replacing at random by the cache replacement policy from the low priority block when the cache area is full after giving priority to the trigger block. We analyzed using the memory simulator program gem5 and PARSEC benchmark to assess the performance of the hardware prefetcher. As a result, compared to the existing hardware prefecture to generate the spatial region using a bit vector, L1 data cache miss rate was reduced about 44.5% on average and an average of 26.1% of L1 instruction misses occur. In addition, IPC (Instruction Per Cycle) showed an improvement of about 23.7% on average.

Epidemiological and Serological Investigation on Epidemic Encephalitis in Korea (우리나라 유행성뇌염(流行性腦炎)의 역학적(疫學的) 및 혈청학적(血淸學的) 조사연구(調査硏究))

  • Lee, Chu-Won;Kim, Kyung-Ho;Kim, In-Dal
    • Journal of Preventive Medicine and Public Health
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    • v.7 no.2
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    • pp.403-415
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    • 1974
  • The author has investigated epidemiological features of human cases of epidemic encephalitis (E. E.) in the Republic of Korea and the status of antibody requisition in pre-and post-epidemic time. And virological and serological studies with regarding the relationship of E. E. infection between human and piglet, and field survey against its vector by means of virus isolation from mosquitoes were carried out. Finally, vaccine field trial against human population has also been evaluated in order to confirm its effectiveness. The results of the studies are summarized as follows : 1. The annual incidence of reported cases during the past 25 years (1949-1973) in the Republic of Korea has shown two patterns, one was typical cyclic incidence and the other one was irregular. Annual average morbidity and mortality rate per 100,000 population were 5.7 and 2.1 and fatality rate was 34.6% in typical cyclic years. 2. With regard to the geographical distribution of E. E., the province of Jeolla-Bug-Do illustrated the highest incidence regardless of the epidemic size. 3. The main epidemic period was between mid-August and mid-September (above 90% of the total number of cases). The first case was reported in middle of July and the epidemic ceased in late of October. 4. An analysis of the age distribution of cases of E. E., has shown that above 90% of the total cases occurred in the age groups under 14 years and it was noted that about its 54% were occurred in the age groups between 5-9 years group. 5. Through the Haemagglutination Inhibition (H-I) test for the laboratory diagnosis of E. E., it was found that higher H-I antibody titer was usually detected in the convalescent phase, 15 days after onset. 6. The H-I antibody survey against 563 healthy population by age groups during the pre-epidemic season showed that 422(75%) were less than H-I titer, 1:20 and 122(21.7%) were positive H-I titer, 1:20. Among the 94 American in Seoul who had not been in E. E. endemic area previously only one person had appeared sero-conversion as a H-I titer of 1:80 after post-epidemic season. 7. The E. E. virus could be isolated from the mosquitos pools-C, tritaeniorhyncus which were caught between late July and middle August. 8. E.E. Virus was also isolated from piglet blood on early August and H-I antibody conversion was occurred mostly on middle of August. 9. H-I antibody sero-conversion rate reached to high level when vaccine purified by mouse brain tissue inoculated, showing 98.9%. Higher antibody titer was acquired when booster inoculation was performed, Four fold rise of H-I add N-T antibodies was confirmed with 93.2% and 82.1% respectively.

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ACQUISITION OF THE FLIGHT INFORMATION USING THE KSR-3 MAGNETOMETER (KSR-3 탑재 자력계를 이용한 비행정보 획득 연구)

  • Kim, Sun-Mi;Jang, Min-Hwan;Lee, Dong-Hun;Han, Young-Seok;Kim, Jun;Hwang, Seung-Hyun;Lee, Eun-Seok;Lee, Sun-Min;Kim, Hyo-Jin;Lee, Su-Jin
    • Journal of Astronomy and Space Sciences
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    • v.20 no.1
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    • pp.29-42
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    • 2003
  • The KSR-3 magnetometers consist of the fluxgate magnetometer (MAG/AIM) for acquiring the rocket flight attitude information, and the search-coil magnetometer (MAG/SIM) for the observation of the Earth's magnetic fluctuations. The position (latitude, longitude, and height) and flight condition (the transformation angle) of the rocket is measured after the data based on these two magnetometers are compared with IGRF The gap in the vector of magnetic field between the position of the launching point and an impact point is taken into account in data reduction. Angular variation of pitch, yaw, and roll can be researched when the data is applied to the coordinate system of the rocket.

Viruliferous Rate of the Small Brown Planthopper in the Maize Field Infected with Rice black-streaked dwarf virus (옥수수 재배지의 벼검은줄오갈병 매개충인 애멸구의 보독충율)

  • Lee, Bong-Choon;Jung, Ji-Hun;Kim, Jung-In;Yoon, Young-Nam;Hong, Sung-Jun;Kwak, Do-Yeon;Hong, Yeon-Kyu;Kang, Hwang-Won;Lee, Key-Woon
    • Research in Plant Disease
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    • v.14 no.3
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    • pp.226-228
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    • 2008
  • The Rice black-streaked dwarf virus (RBSDV) infected 99-100% of a $1000\;m^2$-maize field in Mungyeong City in 2007. Adjacent to the area is a Persimmon orchard where barley crops were grown under the trees as green manure crops and for soil amendments. The barley acted as winter host to the small brown plant hoppers (SBPH) enabling the insects to survive and pass the winter season. The existence of RBSDV was detected and confirmed by RT-PCR using S9 specific primer. Samples of the insect vector SBPH were collected in the area on May 3, June 7 and, August 4 and the results of the RT-PCR analysis revealed viruliferous insect rates of 2.9, 4.8, and 4.4%, respectively. These observed viruliferous insect rates were similar with those detected in RBSDV infected rice fields.

Developmental disability Diagnosis Assessment Systems Implementation using Multimedia Authorizing Tool (멀티미디어 저작도구를 이용한 발달장애 진단.평가 시스템 구현연구)

  • Byun, Sang-Hea;Lee, Jae-Hyun
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.3 no.1
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    • pp.57-72
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    • 2008
  • Serve and do so that graft together specialists' view application field of computer and developmental disability diagnosis estimation data to construct developmental disability diagnosis estimation system in this Paper and constructed developmental disability diagnosis estimation system. Developmental disability diagnosis estimation must supply information of specification area that specialists are having continuously. Developmental disability diagnosis estimation specialist system need multimedia data processing that is specialized little more for developmental disability classification diagnosis and decision-making and is atomized for this. Characteristic of developmental disability diagnosis estimation system that study in this paper can supply quick feedback about result, and can reduce mistake on recording and calculation as well as can shorten examination's enforcement time, and background of training is efficient system fairly in terms of nonprofessional who is not many can use easily. But, as well as when multimedia information that is essential data of system construction for developmental disability diagnosis estimation is having various kinds attribute and a person must achieve description about all developmental disability diagnosis estimation informations, great amount of work done is accompanied, technology about equal data can become different according to management. Because of these problems, applied search technology of contents base (Content-based) that search connection information by contents of edit target data for developmental disability diagnosis estimation data processing multimedia data processing technical development. In the meantime, typical access way for conversation style data processing to support fast image search, after draw special quality of data by N-dimension vector, store to database regarding this as value of N dimension and used data structure of Tree techniques to use index structure that search relevant data based on this costs. But, these are not coincided correctly in purpose of developmental disability diagnosis estimation because is developed focusing in application field that use data of low dimension such as original space DataBase or geography information system. Therefore, studied save structure and index mechanism of new way that support fast search to search bulky good physician data.

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A Study on Flow Distribution in a Clean Room with Multiple Exits (다수의 출구를 가지는 크린룸 내부의 기류분포에 관한 연구)

  • Lee, Jae-Heon;Lee, Sie-Un;Kim, Sukhyun
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.17 no.4
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    • pp.418-425
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    • 1988
  • Since conventional computer program is workable only with velocity boundary condition, in practical fluid passage such as clean room which usually have wide inlets and outlets, it is not easy to measure velocity itself because of its vector property. Furthermore a certain assumption of velocity at boundaries may lead to physically unreasonable results. From this motivation, we have developed a computer program to predict whole flow field imposed on pressure-based boundary condition which can be measured by relatively simple method. The only additional velocity boundary condition that should be imposed on to make the problem unique, are no slip condition at all walls and zero cross stream velocity at inlet. The result of present study was compared with that by Bernoulli equation being used practically. They were coincident well each other within 5%, therefore the validity of the present method is proved. In the present work, the flow field in a clean room subject to pressure-based boundary conditions at an inlet and two exits was predicted numerically. The pressure difference between the inlet and the left exit which keeps relatively low pressure among two exits is fixed as 150[Pa] and the pressure at the right exit is varied from zero to 150[Pa] by the increment of 25[Pa]. For each cases the flow characteristics in the clean room, the velocity profile at the inlet, and the flow rate through the two exits was predicted. The flow rate through the right exit imposed on relatively higher pressure than the left exit decreased linearly according to the increase of pressure of the right exit. When the pressure of the right exit is increased enough to cause back flow at the exit, the flow rate is rapidly decreased.

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A Method for Prediction of Quality Defects in Manufacturing Using Natural Language Processing and Machine Learning (자연어 처리 및 기계학습을 활용한 제조업 현장의 품질 불량 예측 방법론)

  • Roh, Jeong-Min;Kim, Yongsung
    • Journal of Platform Technology
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    • v.9 no.3
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    • pp.52-62
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    • 2021
  • Quality control is critical at manufacturing sites and is key to predicting the risk of quality defect before manufacturing. However, the reliability of manual quality control methods is affected by human and physical limitations because manufacturing processes vary across industries. These limitations become particularly obvious in domain areas with numerous manufacturing processes, such as the manufacture of major nuclear equipment. This study proposed a novel method for predicting the risk of quality defects by using natural language processing and machine learning. In this study, production data collected over 6 years at a factory that manufactures main equipment that is installed in nuclear power plants were used. In the preprocessing stage of text data, a mapping method was applied to the word dictionary so that domain knowledge could be appropriately reflected, and a hybrid algorithm, which combined n-gram, Term Frequency-Inverse Document Frequency, and Singular Value Decomposition, was constructed for sentence vectorization. Next, in the experiment to classify the risky processes resulting in poor quality, k-fold cross-validation was applied to categorize cases from Unigram to cumulative Trigram. Furthermore, for achieving objective experimental results, Naive Bayes and Support Vector Machine were used as classification algorithms and the maximum accuracy and F1-score of 0.7685 and 0.8641, respectively, were achieved. Thus, the proposed method is effective. The performance of the proposed method were compared and with votes of field engineers, and the results revealed that the proposed method outperformed field engineers. Thus, the method can be implemented for quality control at manufacturing sites.