• Journal of Magnetics
• /
• 제16권2호
• /
• pp.181-185
• /
• 2011

To improve trapped field characteristics of a high temperature superconducting (HTS) bulk, a technique to implement artificial holes has been studied. The artificial holes, filled up with epoxy or metal, may provide better cooling channel and enhance mechanical strength of the HTS bulk. Although many useful researches based on experiments have been reported, a numerical approach is still limited because of several reasons that include: 1) highly non-linear electromagnetic properties of HTS; and 2) difficulty in modeling of randomly scattered "small" artificial holes. In this paper, a 2-D finite element method with iteration is adopted to analyze trapped field characteristics of HTS bulk with artificial holes. The validity of the calculation is verified by comparison between measurement and calculation of a trapped field in a $40{\times}40\;mm$ square and 3.1 mm thick HTS bulk having 16 artificial holes with diameter of 0.7 mm. The effects of sizes and array patterns of artificial holes on distribution of trapped field within HTS bulk are numerically investigated using suggested method.

• The Journal of Asian Finance, Economics and Business
• /
• 제9권3호
• /
• pp.257-263
• /
• 2022

The objective of this study was to see how artificial intelligence applications affected organizational innovation in Jordanian commercial banks. Both independent and dependent variables were measured in three dimensions: expert systems, neural network systems, and fuzzy logic systems for artificial intelligence applications variable. Product innovation, process innovation, and management innovation for the organizational innovation variable. To achieve study objectives, a questionnaire was developed and distributed to a sample of one hundred fifty-three managers in Jordanian commercial banks, who were selected according to the simple random sampling method. Except for the neural network systems dimension, which comes in at an average level, the study indicated that there is a high level of organizational innovation and artificial intelligence applications. Furthermore, the findings revealed that artificial intelligence applications have a significant impact on organizational innovation in Jordanian commercial banks, with the most important artificial intelligence application being a fuzzy logic system. The study suggested keeping track of technological advancements in the field of artificial intelligence applications and incorporating them into banking operations by benchmarking with the best commercial bank practices and allocating a portion of the budget to technological applications and infrastructure development, as well as balancing between technology use and information security risks to ensure client privacy is protected.

• 환경생물
• /
• 제24권2호
• /
• pp.160-165
• /
• 2006

The purpose of this study was to ascertain the prey composition and utilization of the Eurasian otter, Lutra lutra, in the ecosystem conservation region of the Seomjin River. The study was conducted for a 12-month period from March 2003 to February 2004 by spraints analysis and an investigation using artificial holts. We found seasonal variation in the number of spraints and composition of prey items. Fish were the main prey items throughout the period (82%), and other prey items included birds (14%), amphibians (2%) and arthropods (1%). In addition to prey identification, we investigated habitat utilization by otters through spraints distribution. The traces of otters were discovered in five of the six total artificial holts. However, the utilization of the artificial holts in the study area seemed to be limited as evidenced by the low frequency of traces in the holts.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2003년도 춘계 학술발표회논문집
• /
• pp.38-44
• /
• 2003

Artificial blasts, defined as seismo-acoustic events, were discriminated from natural earthquakes in the Korean Peninsula by the seismo-acoustic analysis. Total 197 seismo-acoustic events corresponding to 9 percent of seismic events in 2002 were analyzed and classified as artificial surface blasts. Events distribution pattern of the seismo-acoustic events in 2002 was similar to the previous result in 1999-2001, except for two regions. Newly determined seismo-acoustic events were added to the previous artificial blast database. To extend infrasound detection capability, new small-scale infrasound array(TJIAR) was installed in KIGAM. Preliminary analysis for the small array was conducted to discriminate artificial blasts in the southwestern part of the Korean Peninsula. The small array discriminated S seismo-acoustic events during short period analysis. And two infrasound arrays(TJIAR and CHNAR) were used to determine approximate sound source location by cross bearing method.

• 대한지리학회지
• /
• 제46권3호
• /
• pp.319-330
• /
• 2011

본 연구에서는 지상관측 토양수분, 강수량, 지면온도 및 MODIS NDVI와 인공신경망모형을 이용하여 토양수분 공간분포 산정 모형을 제안하였으며, 신뢰성 높은 토양수분 관측 자료를 보유한 용담댐 유역에 대하여 모형의 적용성을 검증하였다. 토양수분 산정모형의 학습에 사용된 주천, 부귀, 상전의 3개 지점의 경우 약 0.9353의 상관계수와 약 1.4957%의 평균제곱근오차를 보여주며, 검증지점으로 사용된 천천2의 경우에는 약 0.8215의 상관계수와 약 4.2077%의 평균제곱근오차를 보여 토양수분 산정모형의 적용가능성이 높다고 판단된다. 인공위성으로부터 관측된 광역의 식생정보와 자료간의 비선형 상관특성을 잘 구현하는 인공신경망을 활용하여 수립된 토양수분 산정모형을 이용하여 용담댐 유역의 토양수분 공간분포도를 산정한 결과, 용담댐 유역의 대부분을 차지하고 있는 산림지역의 토양수분이 다른 지역에 비하여 높은 수치를 보여주는 토양수분의 분포를 보여주었다. 본 연구를 통해 제시된 토양수분 산정 방법은 광역 토양수분 산정에 유용한 접근법으로 판단된다.

• 한국전자통신학회논문지
• /
• 제18권5호
• /
• pp.817-826
• /
• 2023

본 논문에서는 스마트 그리드 배전 계통에서 선로상의 고장으로부터 계통을 보호하기 위한 인공 신경 회로망을 기반으로 하는 고장 판단 방법론을 제안하였다. 제안된 방법론에서는 먼저 전류 실효값 크기를 기반으로 일반 고장 여부를 판단하고 다음, 정상 전류로 판단되는 경우 인공 신경 회로망을 기반으로 하는 normal/HIF classifier를 이용하여 고 임피던스 지락 고장 여부를 판단하도록 설계하였다. 반복적인 DSP 모듈 기반 알고리즘 검증 시험들 중에서, 실효 값 크기가 최소 동작전류보다 작은 정상 전류 파형 시험인 경우에 normal/HIF classifier가 전류 파형을 정상상태로 인식하여 부 동작하였으며, 반면에, 저 임피던스 고장의 경우는 고장 상태로 인식하여 정해진 절차에 따라 재폐로 동작을 보임으로써 제안된 방법론의 유효성을 확인할 수 있었다.

• 한국초전도ㆍ저온공학회논문지
• /
• 제19권3호
• /
• pp.27-32
• /
• 2017

The effects of artificial holes on the trapped magnetic fields and magnetic levitation forces of very large single-grain $Y_{1.5}Ba_2Cu_3O_{7-y}$ (Y1.5) bulk superconductors were studied. Artificial holes were made for Y1.5 powder compacts by die pressing using cylindrical dies with a diameter of 30 mm or 40 m, or rectangular dies with a side length of 50 mm. The single grain Y1.5 bulk superconductors (25 mm, 33 mm in diameter and 42 mm in side length) with artificial holes were fabricated using a top-seeded melt growth (TSMG) process for the die-pressed Y1.5 powder compacts. The magnetic levitation forces at 77 K of the 25 mm single grain Y1.5 samples with one (diameters of 4.2 mm) or six artificial holes (diameters of 2.5 mm) were 10-17% higher than that of the Y1.5 sample without artificial holes. The trapped magnetic fields at 77 K of the Y1.5 samples with artificial holes were also 9.6-18% higher than that of the Y1.5 sample without artificial holes. The 33 mm and 42 mm single grain Y1.5 samples with artificial holes (2.5 mm and 4.2 mm in diameter) also showed trapped magnetic fields 10-13% higher than that of the Y1.5 samples without artificial holes in spite of the reduced superconducting volume fraction due to the presence of artificial holes. The property enhancement in the large single grain Y1.5 bulk superconductors appears to be attributed to the formation of the pore-free regions near the artificial holes and the homogeneous oxygen distribution in the large Y123 grains.

• 한국초전도ㆍ저온공학회논문지
• /
• 제20권3호
• /
• pp.5-10
• /
• 2018

This study presents that various grain boundary junctions are prepared by controlling the seed orientation combined with an artificial hole in a melt process REBCO bulk superconductor. Large grain YBCO superconductors have been fabricated with various grain boundary junctions that the angle between the grain boundary and the <001> axis of Y123 crystal is $0^{\circ}$, $30^{\circ}$ and $45^{\circ}$, respectively. The presence of the artificial hole is beneficial for the formation of clean grain boundary junction and single peak trapped magnetic field profiles have been obtained. Artificial hole makes two growth fronts meet at a point on a periphery of the artificial hole. The presence of artificial hole is not likely to affect on the distribution of Y211 particles. The newly formed <110> facet lines are explained by the formation of new Y123/liquid interface with (010) crystallographic plane.

• 한국수산과학회지
• /
• 제46권3호
• /
• pp.266-272
• /
• 2013

The objective of this study was to monitor and evaluate the schooling characteristics, including the distribution density (volume backscattering strength) and acoustic size (target strength), of commercially valuable species swimming in response to artificial reefs installed at Suyeong Man, Busan, Korea. Fish aggregations at two artificial reef areas and at a nearby natural rocky reef habitat were recorded and analyzed using a 70 kHz split-beam echo sounder and 330 kHz side-scan sonar from August to September, 2006. An underwater CCTV camera system was also used to observe marine organisms in physical contact with and swimming very close to artificial reefs. During the acoustic observations at three reef sites, useful information about schooling characteristics of fish aggregations responding to artificial reefs were obtained, but more trials are needed to confirm significant differences in schooling behavior and geographical distributions in areas containing natural reef structures and artificial reefs.

• 화약ㆍ발파
• /
• 제36권4호
• /
• pp.9-15
• /
• 2018

발파에 의한 암석의 파쇄도는 적재, 운반과 2차 파쇄로 이어지는 후속공정에 직접적인 영향을 미치므로 파쇄도의 조절은 발파 효율성과 생산비용을 평가하는데 필수적이다. 본 연구에서는 인공절리의 방향에 따른 암석의 파쇄도에 대해 분석하였다. 갱내 암반에 수직 및 수평인공절리를 생성한 후 발파실험을 수행하였다. 생성된 암석파쇄물의 입도분포는 2차원 영상해석 프로그램인 split-desktop으로 평가하였다. 평가결과 수평인공절리가 수직인공절리에 비해 전체적인 암석파쇄물의 크기가 작게 평가되었고, 다양한 크기로 암석파쇄물이 분포하였다. 인공절리의 방향에 따라 대괴발생을 억제하고 암석파쇄물을 일정한 크기 이하로 조절 할 수 있을 것으로 판단된다.