• KOREAN POULTRY JOURNAL
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• v.14 s.156
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• pp.32-37
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• 1982

`88년도 계란 총 수요량은 74억1천5백만개로 산란계 3천7백4십만 수 정도와 닭고기 수요는 17만2천M/T으로 육계 1억7천2백만 수가 필요하게 되며 상시 보유 수수는 3천9십6만수 정도가 된다.

• Feed Journal
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• v.2 no.10
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• pp.84-87
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• 2004

중국의 옥수수 파종면적은 1925년도의 13백만 ha에서 2000년도 전후에는 25백만ha 내외로 약 2배로 확대되었다. 그러나 1998년도의 25백만 ha를 최대로 하여 이후에는 저체상태를 지속하고 있으며 확대 증후는 보이지 않는다.(중략)

• Life and Agrochemicals
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• v.26 no.6 s.209
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• pp.26-29
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• 2005

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.3
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• pp.283-288
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• 2012

Ultra-high-strength steels (UHSSs) are widely used for lightweight automobile parts, and the control of springback is very important in sheet-metal forming. The object of this study is to verify the effects of multi-stage forming process parameters for U-channel-type automobile parts made of UHSS. Finite element analysis is carried out to predict the formability and springback. The main parameters considered for the multi-stage forming process are the die angle, die radius, and punch-forming direction. It is shown that multi-stage forming is very effective for reducing springback, and that a small punch-forming angle and die radius reduce springback, whereas the die angle does not have a large effect.

• Journal of Korean Home Economics Education Association
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• v.30 no.2
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• pp.117-136
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• 2018

The purpose of this study is restructuring the template to apply the 'Backward design' for Home Economics Instruction. This study reviewed the theory of Wiggins and McTighe, the advocates of backward design, and examined the template for version 2.0 of Wiggins and McTighe (2011). In addition, This study analyzed various previous researches using backward design, and drew implications for template restructuring for applying backward design on Home Economics Instruction. In addition, the validity of the template was verified through facial validity through the expert council. Through this process, the final 5 stages (1. Curriculum Analysis → 2. Instructional Design (Learning Experience Design ↔ Evaluation Design (Performance Task Planning) → 3. Instruction Flow → 4. Class guide for each class → 5. Evaluation record, and feedback)suggested templates for applying backward design. Future research will use the restructured assumptions and templates to develop teaching materials in the Home Economics areas of the 2015 revised curriculum. In future research, field research should be carried out on how the Home Economics instruction with backward design affects learners.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.546-551
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• 2017

We examine the morphology and texture of microlites included in the obsidians from the Baekdusan (Mt. Baekdu) and Kyushu (SW Japan) by using an electron microscope. According to the morphological types of microlites, the microlites in the Baekdusan obsidians are classified as Arculites, Asteroidal and Crenulite, whereas those in the Kyushu obsidians as various types of Arculites, Bacillite, Belonites, Crenulite, Furculite, Lath, Margarite, and Scopulites. Specifically, the Arculites in both obsidians show very distinctive crystal relationships, though they are mainly composed of magnetite and pyroxene. The Baekdusan Arculites exhibit the poikilitic texture of pyroxene crystals enclosing multiple magnetite crystals, whereas the Kyushu ones demonstrate the granular and/or intergranular texture of interlocking between magnetite and pyroxene crystals. This distinction can be used to discriminate the provenance of the obsidian artefacts from the prehistoric sites in the Korean Peninsula.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.618-626
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• 2012

The Cretaceous fossil sites of Seoyuri in Hwasun was designated as the Korean Natural Monument No. 487 in November 2007. It provides important resources for paleoenvironmental studies, including theropod trackways, plant fossils, mudcracks, ripple marks, and horizontal bedding. The Cretaceous sedimentary strata contain a wide variety of volcanic pebbles, 5-40 cm in diameter in the lower portion and are overlain by the Late Cretaceous Hwasun andesite. Whole rock absolute K-Ar age determinations were performed on six volcanic pebbles from the Cretaceous sedimentary strata and on two samples from the overlaying Hwasun andesite. These ages indicate that the rocks belong to the period between the Turonian of the late Cretaceous (91-70 Ma) and the Pliocene age of the early Cenozoic ($63.4{\pm}1.2$ and $62.1{\pm}1.2$ Ma). Thus, the K-Ar ages indicate that the maximum geological age of the dinosaur track-bearing sedimentary deposits is about ca. 70 Ma. Therefore, it suggests that the age is comparable to the formation ages of the dinosaur footprints-bearing deposits in Sado area of Yeosu (71-66Ma).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12A
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• pp.1229-1237
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• 2006

IEEE 802.11 has employed distributed coordination function (DCF) adopting carrier sense multiple access with collision avoidance (CSMA/CA). To effectively resolve collisions, DCF uses binary exponential backoff (BEB) algorithm with three parameters, i.e., backoff stage, backoff counter and contention window. If a collision occurs, stations involving in the collision increase their backoff stages by one and double their contention window sizes. However, DCF with BEB wastes wireless resource when there are many contending stations. Therefore, in this paper, to enhance the performance of wireless LAN, we propose binary negative-exponential backoff (BNEB) algorithm which maintains a maximum contention window size during collisions and reduces a contention window size to half after successful transmission of a frame without retransmissions. For IEEE 802.11, 802.11a and 802.11b standards, we also compare the performance of DCF with BEB to that with BNEB.

• The KIPS Transactions:PartA
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• v.18A no.3
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• pp.115-122
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• 2011

It is very hard to obtain a general algorithm for solution of all the constraint satisfaction optimization problems. However, if the whole problem is separated into subproblems by characteristics of decision variables, we can assume that an algorithm to obtain solutions of these subproblems is easier. Under the assumption, we propose a problem classifying rule which subdivide the whole problem, and develop backtracking algorithms fit for these subproblems. One of the methods of finding a quick solution is efficiently arrange for any order of the search tree nodes. We choose the cluster head positioning problem in wireless sensor networks in which static characteristics is dominant and interference minimization problem of RFID readers that has hybrid mixture of static and dynamic characteristics. For these problems, we develop optimal variable ordering algorithms, and compare with the conventional methods. As a result of classifying the problem into subproblems, we can realize a backtracking framework for systematic search. We also have shown that developed backtracking algorithms have good performance in their quality.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.5
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• pp.11-116
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• 2000

A topology decreased switching loss and voltage stress by zero voltage switching is presented in this paper. Generally, Switching mode converting productes voltage stress and power losses due to excessive voltage and current. which affect to performance of power supply and reduce overall efficiency of equipments. Virtually, In flyback converter, transient peak voltage and current at switcher are generated by parasitic elements. To solve these problems, present ZVS flyback converter topology applied a auxiliary circuit. Incorporation of auxiliary circuit into a conventional flyback topology serves to reduce power losses and to minimize switching voltage stress. Snubber capacitor in auxiliary circuit serves ZVS state by control voltage variable time at turn on and off of main switch, then reduces voltage stress and power losses. The proposed converter has lossless switching in variable load condition with wide range. A detailed analysis of the circuit is presented and the operation procedure is illustrated. A (50W 100kHz prototype) ZVS flyback converter using a auxiliary circuit is built which shows an efficiency improvement as compared to a conventional hard switching flyback converter.