• 한국농공학회지
• /
• 제36권2호
• /
• pp.123-131
• /
• 1994

Experimental studies were conducted to make clear the soil moisture environment under the condition of paddy-upland rotational fields by investigating water-table depths and soil moisture contents during growing season of crops in two kinds of soil. The following results were obtained. 1.Although water-table depths fluctuated with the amount of rainfall in the experimental field, it seemed that the variation of vater4able depths in the paddy-upland rotational, field was strongly affected by the condition of locations on paddy fields. 2.It is recognized that the concept of sum of excess water depth(SEWxx) and sum of excess water day(SEDxx) can be used to represent the soil moisture stress index due to the fluctuation of water-table depths. 3.The results of this study clearly indicate that drainage in paddy-upland rotational field to maintain an optimum soil moisture content must be made by introducing the concept of block drainage which needs both subsurface drainage and intercept drainage around a field. 4.Soil moisture contents were affected by both the amount of rainfall and water-table depths, however, the moisture content for top soil showed higher correlation with the amount of rainfall while that for subsoil with water-table depths.

• 한국초등과학교육학회지:초등과학교육
• /
• 제26권5호
• /
• pp.570-579
• /
• 2007

Instructional objectives clearly show what teachers should teach in the class and how they lead the class, focusing on a certain activity for their students in the class. Clear instructional objectives are a prerequisite for teachers to accomplish effectively their curriculum. The revised Bloom's taxonomy table of educational objectives has been introduced in 50 years since the publication of his original taxonomy table in 1956. Bloom's revised taxonomy table of educational objectives has two-dimensions, the "cognitive process" dimension and the "knowledge" dimension, and it classifies class objectives more elaborately and clearly. This study was designed to classify instructional objectives stated in elementary science guidebooks for teachers into Bloom's revised taxonomy table, and see how the objectives of elementary science classes were categorized by grade level and areas. In addition, this study examined how the objectives of elementary science classes by study area were classified into the new taxonomy table. This study classified 618 elementary science instructional objectives of third- to sixth-grade science guidebooks for teachers into Bloom's revised taxonomy table. The results showed that the objectives of elementary science classes emphasized disproportionately some of the knowledge and cognitive process dimensions. In the area of subjects while the percentages of factual knowledge were very high, those of meta-cognitive knowledge were low.

• 조명전기설비학회논문지
• /
• 제28권11호
• /
• pp.112-122
• /
• 2014

This paper proposes a PMSM torque control method considering DC-link voltage variation and friction torque. In general EV/HEV application, two dimensions look-up table(2D-LUT) is used for reference current generation due to its stable and robust torque control performance. Conventionally, this 2D-LUT is established by flux-torque table to overcome the DC-link voltage variation. However, the flux table establishment is more complex than the speed table establishment. Moreover, one flux data reflects several speed conditions in variable DC-link voltage, friction torque cannot be considered by using the flux table. In this paper, speed-torque 2D-LUT is used for current reference generation. With this table, PMSM torque control is well achieved regardless of DC-link voltage variation by the proposed control method. Simulation and experimental results validate improvement of torque control error through friction torque compensation.

• Journal of Communications and Networks
• /
• 제13권4호
• /
• pp.408-417
• /
• 2011

The stringent performance requirement for the high efficiency of routing protocols on the Internet can be satisfied by exploiting the threaded border gateway protocol (TBGP) on multi-cores, but the state-of-the-art TBGP performance is restricted by a mass of contentions when racing to access the routing table. To this end, the highly-efficient parallel access approach appears to be a promising solution to achieve ultra-high route processing speed. This study proposes a general routing table structure consisting of two-level tries for fast parallel access, and it presents a heuristic-based divide-and-recombine algorithm to solve a mass of contentions, thereby accelerating the parallel route updates of multi-threading and boosting the TBGP performance. As a projected TBGP, this study also modifies the table operations such as insert and lookup, and validates their correctness according to the behaviors of the traditional routing table. Our evaluations on a dual quad-core Xeon server show that the parallel access contentions decrease sharply by 92.5% versus the traditional routing table, and the maximal update time of a thread is reduced by 56.8 % on average with little overhead. The convergence time of update messages are improved by 49.7%.

• Earthquakes and Structures
• /
• 제6권5호
• /
• pp.539-560
• /
• 2014

Shaking tables are devices for testing structures or structural components models with a wide range of synthetic ground motions or real recorded earthquakes. They are essential tools in earthquake engineering research since they simulate the effects of the true inertial forces on the test specimens. The destructive earthquakes that occurred at the north part of Algeria during the period of 1954-2003 resulted in an initiative from the Algerian authorities for the construction of a shaking simulator at the National Earthquake Engineering Research Center, CGS. The acceleration tracking performance and specifically the inability of the earthquake simulator to accurately replicate the input signal can be considered as the main challenge during shaking table test. The objective of this study is to validate the uni-axial sinusoidal performances curves and to assess the accuracy and fidelity in signal reproduction using the advanced adaptive control techniques incorporated into the MTS Digital controller and software of the CGS shaking table. A set of shake table tests using harmonic and earthquake acceleration records as reference/commanded signals were performed for four test configurations: bare table, 60 t rigid mass and two 20 t elastic specimens with natural frequencies of 5 Hz and 10 Hz.

• 한국비블리아학회지
• /
• 제14권1호
• /
• pp.141-157
• /
• 2003

본 연구는 대학도서관간의 자원의 공유를 위한 DDC 표준재전개표 개발을 위하여 DDC를 사용하는 대학도서관들 중 재전개표 사용 여부에 대한 조사와 재전개 내용에 대해서 조사하였다. 이 연구에서 제시한 표준 재전개표의 주요 내용은 Table 2, Table 5, Table 6과, 000 총류, 100 철학 중 동양철학, 200 종교 중 불교와 동양발생 제종교, 300 사회과학 중 행정학, 400언어학, 800 문학, 900 지리 및 역사로 한정하였다. 본 연구에서 DDC에 임의규정이 없는 경우는 보편성의 원리에 따라 이를 적용하였고 그 외의 대부분의 재전개는 임의규정에 충실하였다. 본 연구의 결과는 국내 대학도서관이 소장하고 있는 지식정보의 공유에 기여할 뿐 아니라 KDC를 개정하기 위한 기초자료로 활용할 수 있을 것이다.

• 한국지능시스템학회논문지
• /
• 제14권3호
• /
• pp.290-297
• /
• 2004

운반차-막대 시스템을 위한 제어 법칙들의 계략을 관찰하여, 운반차-막대 시스템의 상태 벡터와 제어 법칙의 출력 사이에 우함수적인 대칭성이 내재하는 것을 규명하였다. 제어 법칙을 look-up table에 구현하는데 있어서 상태 변수들의 양자화와 제어 법칙의 학습에 대칭성을 반영하는 문제를 토의하고, CMAC이 대칭성을 반영하여 운반차-막대 시스템의 비선형 제어 법칙을 학습한 결과를 관찰하였다. 대칭성을 반영함으로써 look-up table에 제어 법칙이 구현되는 학습 기간이 단축되고 소요되는 메모리 량을 크게 줄일 수 있으면서도, 시스템의 상태와 제어 법칙 사이의 대칭성이 보존되는 학습 성능의 개선을 확인하였다.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2008년도 춘계 종합학술대회 논문집
• /
• pp.66-68
• /
• 2008

본 논문에서는 사용자 상호협업 테이블 탑 디스플레이 인터페이스에 대하여 기술한다. 기존의 인터페이스와의 가장 큰 차이점은 기존의 연구에서는 하나의 디바이스를 통하여 여러 명의 사용자가 동시에 사용이 가능한 face to face의 방식을 지향한 반면, 협업을 중요시한 테이블 탑 디스플레이에서는 device to device의 방식을 지향하여 한 디바이스에 한 명의 사용자를 요구한다. 이렇게 협업을 중시한 연구가 활발히 이루어지고 있으나 아직은 해결해야 할 문제점이 많은 실정이다. 본 논문에서는 협업을 위한 테이블 탑 디스플레이 인터페이스에 대하여 세계적 동향을 알아보기 위해 사용자들과의 상호협업이 가능한 테이블 탑 디스플레이들에 대한 인터페이스에 대하여 알아보고, 현재 개발중인 사용자들간의 상호협업이 가능한 테이블 탑 디스플레이에 대하여 기술한다.

• 한국표면공학회지
• /
• 제5권2호
• /
• pp.1-4
• /
• 1972

We have studied about the optimum chemical etching and sensitizing conditions of the plating on plastics. As specimen 'Mitzubishi Nobren MM2A' was used. The results were as follow. 1) The optimum chemical etching conditions. Etched the specimens for $10{\sim}40$ minutes at $70{\sim}80^{\circ}C$ with the etching solution of table 1, and for $10{\sim}15$ minutes at $65{\sim}70^{\circ}C$ with the etching solution of table 2 Table 1. Etching solution (I) Composition : $H_2SO_4(95%)-Component : 250 ml, Composition : $H_3PO_4(85%)$ - Component : 75ml, Composition : $K_2Cr_2O_7$ - Component : 12.5g, 2) The optimum sensitizing conditions. Sensitized the specimens for $60{\sim}90$ seconds at $25^{\circ}C$ with the sensitizing solution of table 3 Table 2. Etching solution (II) Composition : $H_2SO_4(95%)$ - Component : 22.5ml, Composition : $H_3PO_4(85%)$ - Component : 15ml, Composition : $CrO_3$ - Component : 105g, Composition : Water - Component : 150 ml, Table 3. Sensitizing solution Composition : $SnCl_2$ - Component : 9g, Composition : HCl(35%) - Component : 36ml, Composition : Water - Component : 300 ml

• 전자공학회논문지
• /
• 제52권4호
• /
• pp.23-29
• /
• 2015

본 논문에서는 수중 위치 추적(Underwater Localization)을 위한 수평거리 추정 방식 중 음선의 각도 변화를 이용하는 방식을 개선하는 Look-up Table(LUT)를 사용하는 방식을 제안하고 기존 방식과의 연산속도 및 수평거리 오차를 비교한다. LUT를 사용하여 추정하는 방식은 수신기의 음파 도달 시간(Time of arrival : ToA)과 깊이에 따른 Sound Speed Profile(SSP)을 이용하여 만들어진 수평 거리-ToA table을 이용한다. 결과적으로, 음선의 각도 변화를 이용하는 방식에 비해 수평거리 추정오차는 다소 증가하게 되지만, 수신된 ToA에 대응되는 수평거리를 사용한다는 점에서 실시간으로 각도 변화를 추정하는 기존방식에 비하여 매우 빠른 처리가 가능하다.