• 제목/요약/키워드: Tat

검색결과 309건 처리시간 0.038초

Factors Affecting Training Quality and Student Satisfaction: An Empirical Study in Vietnam

  • LE, Duong Thi Hai;NGUYEN, Long Duc Bao;PHAN, Chau Le Ngoc;VU, Tuan Minh;PHAN, Hien Thu
    • The Journal of Asian Finance, Economics and Business
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    • 제9권4호
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    • pp.391-398
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    • 2022
  • The purpose of this study was to determine the factors that influence the training quality of Van Lang University's Finance Banking faculty (VLU). Another goal was to discover a way to increase training quality and give students the greatest experience possible. To achieve the following goals, qualitative research was used in combination with questionnaires and document reviews. A total of 700 surveys were sent out, with 624 responses. In-depth interviews with 12 graduates were conducted during the qualitative stage to obtain their perspectives on their time at VLU. The impact of five factors (instructor qualification, facility, education program, accessibility, and student interaction) was investigated in this study, and the findings revealed that all of them significantly mediated the relationship with the training quality of VLU's Finance Banking faculty. The findings show that it is vital to improve the training quality to increase student satisfaction and boost their academic abilities. With the framework from this study, policymakers, researchers, and institutes can cooperate in developing and upgrading the general training quality at higher education institutions in Vietnam. Improving the training quality of a faculty will continue to be a challenge. Therefore, this is a topic that requires continuous research.

급속충전기용 파워 모듈을 위한 단일단 AC-DC 컨버터 (A Single-Stage AC-DC Power Module Converter for Fast-Charger)

  • 레덧탕;최세완
    • 전력전자학회논문지
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    • 제27권5호
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    • pp.384-390
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    • 2022
  • In this study, a single-stage, four-phase, interleaved, totem-pole AC-DC converter is proposed for a super-fast charger station that requires high power, a wide voltage range, and bidirectional operation capabilities and adopts various types of electric transport vehicles. The proposed topology is based on current-fed push-pull dual active bridge converter combined with the totem-pole operation. Owing to the four-phase interleaving effect, the bridge on the grid side can switch at 0.25, 0.5, and 0.75 to achieve a ripple-free grid current. The input filter can be removed theoretically. Switching methods for the duty of the secondary-side duty cycle are proposed, and they correspond to the primary duty cycle for reducing the circulating power and handling the total harmonic distortion. Therefore, the converter can operate under a wide voltage range. Experimental results from a 7.5 kW prototype are used to validate the proposed concept.

파형 단면을 가진 유하식 집열기의 열적 성능에 대한 이론 및 실험 연구(I) (An Analytical & experimental study on the thermal performance of trickle solar collector with Sinuous Cross-section)

  • 이종호;정모;백남춘;오정무
    • 대한설비공학회지:설비저널
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    • 제12권4호
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    • pp.240-251
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    • 1983
  • The municipal government of Daejeon, Korea set up a plan to retrofit solar energy to the existing swimming pool. The pool was constructed in 1980, and meets the requirements of International standard. It will be used for the 1986 Asian Games and the 1988 Seoul Olymipics. The roof structure of the existing pool is to be modified to accomodate trickle solar collectors. In addition, various energy conserving ideas will be applied to the existing building structure. For the prevention of over heating of collectors on the roof, natural air convection scheme will be adopted within the collector system. Natural convection of passive type heating would be also adopted for the space heating of the pool when the system is idle. At present, the pool can be utilized only for two months a year without auxilairy heating. With oil heating, the energy cost would be too high for the normal operation. When this project completed in March 1984, it would be expected to be openable for seven months a year without a significan amount of auxiliary heating. In this project, two dimensional numerical analysis technic have been used to analyse the characterisitics of thermal performance of the swimming pool system. An experimental tat verification of the theoretical analysis have been also attempted.

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반도체 공정에서 가상계측 위한 XGBoost 기반 예측모델 (XGBoost Based Prediction Model for Virtual Metrology in Semiconductor Manufacturing Process)

  • 한정석;김형근
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2022년도 춘계학술발표대회
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    • pp.477-480
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    • 2022
  • 반도체 성능 향상으로 신호를 전달하는 회로의 단위가 마이크로 미터에서 나노미터로 미세화되어 선폭(linewidth)이 점점 좁아지고 있다. 이러한 변화는 검출해야 할 불량의 크기가 작아지고, 정상 공정상태와 비정상 공정상태의 차이도 상대적으로 감소되어, 공정오차 및 공정조건의 허용범위가 축소되었음을 의미한다. 따라서 검출해야 할 이상징후 탐지가 더욱 어렵게 되어, 높은 정밀도와 해상도를 갖는 검사공정이 요구되고 있다. 이러한 이유로, 미세 공정변화를 파악할 수 있는 신규 검사 및 계측 공정이 추가되어 TAT(Turn-around Time)가 증가하게 되었고, 웨이퍼가 가공되어 완제품까지 도달하는데 필요한 공정시간이 증가하여 제조원가 상승의 원인으로 작용한다. 본 논문에서는 웨이퍼의 검계측 데이터가 아닌, 제조공정 과정에서 발생하는 다양한 센서 및 장비 데이터를 기반으로 웨이퍼 제조 결과가 양품인지 그렇지 않으면 불량인지 구별할 수 있는 가상계측 모델을 제안한다. 기계학습의 여러 알고리즘 중에서 다양한 장점을 갖는 XGBoost 알고리즘을 이용하여 예측모델을 구축하였고, 데이터 전처리(data-preprocessing), 주요변수 추출(feature selection), 모델 구축(model design), 모델 평가(model evaluation)의 순서로 연구를 수행하였다. 결과적으로 약 94% 이상의 정확성을 갖는 모형을 구축하는데 성공하였으나 더욱 높은 정확성을 확보하기 위해서는 반도체 공정과 관련된 Domain Knowledge 를 반영한 모델구축과 같은 추가적인 연구가 필요하다.

주파수 선택적 다중 경로 페이딩 채널에서 불완전 전력 제어를 고려한 동기식 DS-CDMA 시스템의 수용 용량 (Capacity of synchronous DS-CDMA system on frequency selective multipath fading channels with imperfect power control)

  • 황승훈;김용석;김동희;황금찬
    • 한국통신학회논문지
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    • 제25권3A호
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    • pp.342-350
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    • 2000
  • 본 논문에서는 주파수 선택적 레일리 페이딩 채널에서 불완전 전력 제어의 영향을 고려한 동기식 DS-CDMA 시스템의 역방향 링크 수용 용량이 분석된다. 불완전한 전력 제어의 영향을 분석하기 위해서, 코히어런트 RAKE 수신기를 가지는 동기식 DS-CDMA 시스템에서 수신 신호의 대수 정규 분포 표준편차를 고려한다. 불완전한 전력 제어가 존재하는 경우, 다중 경로 채널 전력 지연 프로파일 모양과 다중 경로의 수가 동기식 DS-CDMA 시스템의 성능에 미치는 영향을 살펴보고 또한 시스템 수용 용량을 추정하기 위해서 부호화된 비트 오류 확률이 계산되어진다. 그리고, 동기식 CDMA의 성능을 기존의 비동기식 CDMA 성능과 비교하여, 불완전한 전력 제어가 존재하는 상황에서 얻을 수 있는 수용 용량의 이득을 예측해본다.

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관측과 모델에서 얻어진 열대 대서양에서의 계절별 염분 분포 및 담수 효과 (Observed and Simulated Seasonal Salinity in The Tropical Atlantic ocean, and its Relationship with Freshwater)

  • 유정문
    • 한국해양학회지
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    • 제27권4호
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    • pp.290-302
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    • 1992
  • 기후학적인 관측자료와 담수 효과를 고려한 수치실험에서 얻어진 두가지의 계절별 염분 분포를 열대 대서양 500 m 상층부에 대하여 조사하였다. 해표면 염분의 계절 변 화는 담수의 초과를 가져오는 열대수렴대(ITCZ)의 이동 및 강물 방출 시기에 밀접한 관계가 있었다. 본 연구에서 얻어진 계절별 염분 분포는 Defant (1981)와 Levitus (1982) 등의 이미 존재하는 기후 자료와 대체로 비슷하나, 본 연구의 자료가 온도 분 포에 더 잘 일치하였다. 밀도에 대한 온도 효과와 비교할 때 염분 효과는 100 m 이심 에서는 무시할 만하나 혼합층에서 염분 효과는 상당히 중요하였다. 관측된 염분 분포 와 모델에서 계산된 염분 분포사이에 뚜렷한 차이가 염분값의 위도에 따른 기울기에서 나타났다. 모델에서 유도된 염분은 관측값보다 적도부근의 해양에서 대체로 높게 나타 났으나, 아열대 해역에서는 낮게 나타났다. 남동 대서양 해역과 같은 관측자료가 매우 적은 곳에서 염분 차이는 크게 나타났고, 이런 해역에서 정교한 모델값이 좀 더 정확 한 듯 보인다. 또한 관측값과 모델에서 얻어진 값과의 불일치에 대한 가능한 원인들도 분석하였다.

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느타리버섯속(屬)의 DNA 다형성분석(多型性分析)에 영향(影響)을 미치는 PCR 조건(條件) (Parameters Affecting Polymerase Chain Reaction in RAPD Analysis of Pleurotus spp.)

  • 김범기;정미정;이창수;이희경;유영복;유진창
    • 한국균학회지
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    • 제23권3호통권74호
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    • pp.202-208
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    • 1995
  • 본 실험결과 느타리버섯속에서의 재현성 있는 최적 RAPD 조건은 $50\;{\mu}l$ 반응액에서 80 ng template DNA, 30 pmole primer, $200\;{\mu}M$ dNTP, 2 mM $MgCl_2$, 50 mM KCl, 10 mM Tris-HCI(pH 9.0), 0.1% Triton X-100, 1.5 unit Taq polymerase(promega)였다. 여섯 개의 primer가 Pleurotus속 8종의 균주에서 RAPD polymorphism을 보임을 알 수 있었으며, 이들의 염기배열은 PR2(GGG GGG AAG C), PR3(GCG GTT GAG G), PR4(CGC ACC GCA C), PR10(CAA TCG CCG T), PR11(CAG CAC CCA C), PR17(TAG GCG TAT CAG GAG GCC CT)이었다.

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Implications of using a 50-μm-thick skin target layer in skin dose coefficient calculation for photons, protons, and helium ions

  • Yeom, Yeon Soo;Nguyen, Thang Tat;Choi, Chansoo;Han, Min Cheol;Lee, Hanjin;Han, Haegin;Kim, Chan Hyeong
    • Nuclear Engineering and Technology
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    • 제49권7호
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    • pp.1495-1504
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    • 2017
  • In a previous study, a set of polygon-mesh (PM)-based skin models including a $50-{\mu}m-thick$ radiosensitive target layer were constructed and used to calculate skin dose coefficients (DCs) for idealized external beams of electrons. The results showed that the calculated skin DCs were significantly different from the International Commission on Radiological Protection (ICRP) Publication 116 skin DCs calculated using voxel-type ICRP reference phantoms that do not include the thin target layer. The difference was as large as 7,700 times for electron energies less than 1 MeV, which raises a significant issue that should be addressed subsequently. In the present study, therefore, as an extension of the initial, previous study, skin DCs for three other particles (photons, protons, and helium ions) were calculated by using the PM-based skin models and the calculated values were compared with the ICRP-116 skin DCs. The analysis of our results showed that for the photon exposures, the calculated values were generally in good agreement with the ICRP-116 values. For the charged particles, by contrast, there was a significant difference between the PM-model-calculated skin DCs and the ICRP-116 values. Specifically, the ICRP-116 skin DCs were smaller than those calculated by the PM models-which is to say that they were under-estimated-by up to ~16 times for both protons and helium ions. These differences in skin dose also significantly affected the calculation of the effective dose (E) values, which is reasonable, considering that the skin dose is the major factor determining effective dose calculation for charged particles. The results of the current study generally show that the ICRP-116 DCs for skin dose and effective dose are not reliable for charged particles.

노년층 여성들의 의복구매유형에 따른 의복구매불만 (The Anxiety in Purchasing According to Clothes Buying Style in Elderly Women)

  • 배현숙
    • 대한가정학회지
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    • 제35권1호
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    • pp.373-388
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    • 1997
  • This research was intended to understand the degree of variety in elderly women by was of classifying the type of clothing purchase's according to the degree of anxiety when they buy clothes. Samples were 285 elderly women who are aged over 55 dwelling in Busan Meropolitan city and this research is made available by the method of the questionnaire interview. The data was analyzed using reliability ANOVA regression Scheffe Test and correlation. The results of the study were the followings 1. The most important factors in the type of clothing purchase's of elder women are the styles disparity of age is represented similarly except the styles of a Brand Loyal tat ranked highest were among the age group 60-64. 2, The factor of difference in clothing purchase's according to degree of education are Brand loyal Cautious Impulsive Ecologists and Experimenters and the style of clothes buying according to activity of leisure are Brand Loyal and conformists. The factor of difference in clothing buying according to shopping companion are Planners Experiments Conformists Impulsive and Persuasible and the item represents difference according to payer for clothing marked all style of clothes buying and similarity except Impulsive and Style-Conscious, 3, The highly correlated item in the degree of education and activity of leisure in the context of the correlated item concerning about shopping companion and payer for clothes are Experimenters impulsive and Ecologists. The colthing anxiey which is highly related is the degree of education and the activity of leisure and the anxiety in masterial colour and self-harmony and the anxiety of colthing purchase's which is highly correlated in clothing purchase's companion and payer for clothin proved the priceand the anxiety of decision-making 4. Economy-Minded Experimenters Impulsive Planners and Style-Conscious represents all of the difference in all items in clothing purchase's Conformists represents anxiety to all items except the anxiety in clothing administration, Cautious and Ecologists represents the differences only for the anxiety in clothing administration,. But Brand-Loyal and Persuasible feels no anxiety in clothing purchase. 5. The most explicable independent variable based upon the analysis of regression in anxiety of colthing purchase is Economy-Minded and the next is Conformist Experiments Planners Style-Conscious Impulsive and so on.

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Morphological and Molecular Characterization of Lymnaeid Snails and Their Potential Role in Transmission of Fasciola spp. in Vietnam

  • Dung, Bui Thi;Doanh, Pham Ngoc;The, Dang Tat;Loan, Ho Thi;Losson, Bertrand;Caron, Yannick
    • Parasites, Hosts and Diseases
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    • 제51권6호
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    • pp.657-662
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    • 2013
  • Freshwater snails of the family Lymnaeidae play an important role in the transmission of fascioliasis worldwide. In Vietnam, 2 common lymnaeid species, Lymnaea swinhoei and Lymnaea viridis, can be recognized on the basis of morphology, and a third species, Lymnaea sp., is known to exist. Recent studies have raised controversy about their role in transmission of Fasciola spp. because of confusion in identification of the snail hosts. The aim of this study is, therefore, to clarify the identities of lymnaeid snails in Vietnam by a combination of morphological and molecular approaches. The molecular analyses using the second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA clearly showed that lymnaeids in Vietnam include 3 species, Austropeplea viridis (morphologically identified as L. viridis), Radix auricularia (morphologically identified as L. swinhoei) and Radix rubiginosa (morphologically identified as Lymnaea sp.). R. rubiginosa is a new record for Vietnam. Among them, only A. viridis was found to be infected with Fasciola spp. These results provide a new insight into lymnaeid snails in Vietnam. Identification of lymnaeid snails in Vietnam and their role in the liver fluke transmission should be further investigated.