• 한국수학교육학회지시리즈E:수학교육논문집
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• 제22권2호
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• pp.137-164
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• 2008

대수 교육은 전통적으로 중등 교육과정 중심의 기호의 조작 및 방정식의 풀이에 초점이 맞추어져 왔다. 그러나 초등 교육과정 전반에 걸친 수에 관한 광범위한 경험은 대수에서 강조되는 기호 및 구조에 기초가 될 수 있다. 본 연구는 초등학교 4학년을 대상으로 실시한 수업 사례를 바탕으로 학생들이 실제로 대수적 사고를 어떻게 구성해나가는지를 면밀하게 탐색하였다. 분석 결과 학생들은 구체물의 조작이나 그림그리기 등의 활동을 통해 규칙성을 인식하기 시작했고, 주어진 문제 상황을 표현하기 위해 다양한 산술적이고 비형식적인 전략을 사용하였으며, 외형이 다른 두 식의 동치관계를 식의 변형과정이 아닌 주어진 문제 상황과의 관계를 이용하여 이해하는 특징을 보였다. 또한, 문제 상황을 대수식으로 표현하는 과정에서 몇 가지 오류를 범했다. 본 연구는 구체적인 수업 사례를 바탕으로 초등학생들의 대수적 사고를 산술적 사고 및 비형식적 사고와 의미 있게 연결하는 대수 지도 방안에 대한 시사점을 제공한다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 21세기 한반도 농업전망과 대책(한국작물학회.한국육종학회 공동주관 심포지움 회보)
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• pp.134-158
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• 1998

The objectives of this article are to identify the current status of agricultural infrastructure in North Korea and to suggest some cooperation measures among South and North Koreas and international agencies in order to develop the North Korea's agricultural infrastructure. The area of cultivated land in North Korea is 1,992 thousand ha (paddy field: 585 thousand ha: upland: 1,407 thousand ha) in 1997. Major water use facilities in North Korea are 1,900 reservoirs (included 100 big dams), 36,400 irrigation pumping stations, 1,600 drainage pumping stations, and 14'a,000 wells. In addition, there is 'two thousand Ri canal construction project' linking the rivers of Aprok, Daeryong, Daedong, Jaeryong, and Yesong. The unit of paddy land consolidation is about 1 ha which is regarded as rational for agricultural mechanization. The project of 'Darak' upland construction to create small size farmland, which has been carried out since 1976 has been unsuccessful due to the shortage of construction equipment. The area of farmland created by reclamation by 1995 is only 75 thousand ha although the potential project area is at)out 320 thousand ha along the western coast. It is due to the fact that civil engineering technologies and equipments are old and investment funds are insufficient. These are a few suggested areas of cooperation among South and North Korea and international agencies in order to improve North Korea's agricultural infrastructure : i) see land reclamation and land consolidation projects to increase paddy fields for rice production; ii) rehabilitation project in farm land areas devastated by flood; and iii) agricultural water development project which including diagnosing and rehabilitating irrigation and drainage facilities.

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.423-430
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• 2001

The purpose of this study is to develop high-speed rotary tillage system for a power tiller by improving the rotary blade and the power train of transmission. Mechanical structure of gear train of rotary drive of conventional power tiller was simplified so that power can be transmitted directly from second shaft to tilling speed change shaft by rotating freely the transfer gear which changes the direction of rotation of shafts using needle bearing installed into middle shaft. A new gear train suitable for the single-edged rotary blade and high-speed rotary drive was developed with the rotational speed of rotary shaft faster than 7.5% at 1st-speed and 1.4% at 2nd-speed the one of conventional system by changing the numbers of teeth of gears of middle shaft, tilling speed change shaft and PTO shaft. Using the developed gear train for high-speed rotary drive, field tests were performed to compare tillage performances by the developed single-edged blade and by the conventional double-edged blade. The results showed that the performances by the single-edged blade compared with the one by the double-edged blade was improved about 18% in field capacity, about 34% in fuel consumption, and 9.4% in soil crushing ratio. Therefore, it may be concluded that tillage performance by the single-edged blade was improved compared to the one by the conventional blade. Evaluation of the developed system consisting of single-edged blade and gear train for high-speed rotary drive in field revealed that tillage performance of the developed system was similar to the one of field test conducted using the system consisting of single-edged blade and gear train for rotary drive of conventional power tiller However, considering the higher cone index of the upland field where evaluation was carried out compare to the one of the ordinary paddy field, it may be concluded that tillage performance of the developed rotary tilling system better than the one of conventional system.

• Journal of Biosystems Engineering
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• 제25권5호
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• pp.369-378
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• 2000

The purpose of this study is to developed high-efficient rotary tillage system for a power tiller by improving the rotary blade. A kind of the rotary blade with single-edged blade(DS) was developed that requires lower tillage energy than conventional double-edged blade(CD) on the design theory for Japanese rotary blade. In order to find out the tillage characteristics between the single-edged blade and the double-edged blade for power tiller, experiments were performed in soil-bins which were filled up clay loam, loam and sandy loam, and then analyzed the effects of the factors such as soil texture, travelling speed, rotational speed, and tillage depth to each of the blades. And field tests were carried out to compare tillage performances of the two blades using rotary cultivator driven by conventional power tiller. The results of this study were summarized as follows; 1) On the soil bin experiment, it was found that tillage torque of the single-edged blade was less than the ones of the double-edged blade. The decreasing ratios of maximum tillage torque of the single-edged blade to the ones of the double-edged blade were 1 to 8% at clay loam, 5 to 20% at loam and 9 to 31% at sandy loam, respectively. 2) By the field tests, that the tillage performances with the single-edged blade compared with the double-edged blade was improved about 19% in field capacity, about 34% in fuel consumption, and 12.5% in soil breaking ratio. Furthermore, the fluctuation of engine speed, the variation of exhaust gas temperature, and the amount of soil clogging on the blade and straw wound on the rotary shaft showed lower values with the developed blade than the conventional blade. So, it may be concluded that tillage performance by the developed single-edged blade was improved compared with the one by the conventional double-edged blade.

• 한국의사학회지
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• 제28권2호
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• pp.1-13
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• 2015

Purpose : Local medicinal herb festivals present the history of the Korean medicine and cultural resources in the regions to play an important role in attracting tourists, vitalizing local economy, and improving the local image. Therefore, it is important to understand the origin of the festival and grasp historical and cultural meaning of local medicinal herb festivals. Methods : I compared the books and articles presented in the reference list. Results & Conclusions : Local medicinal herb festivals originates from traditional yangnyeongsi. Since the $17^{th}$ century, yangnyeongsi has grown up as a special market. Implementation of the Daedong Act promoted commodity and monetary economy that helped commerce and industry develop and market grow up. It also made changes in the social status system and yangnyeongsi has been such a historical phenomenon appeared in this social background. The growth of yangnyeongsi contributed to the progress in the private medicine that triggered the gradual transfer of power in the medicine to the private sector which has long been held by the government. In yangnyeongsi, there were many cultural events to attract visitors. It's the same case in China that preserves stages that were used for cultural events in the medicine market to pass down the historic sites while those in Korea are disappearing as yangnyeongsis are being pulled out of the city areas to the suburban areas due to the redevelopment projects. For this reason, restoration of the place for traditional yangnyeongsi should be taken into account through local medicinal herb festivals.

• 한국식품영양학회지
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• 제30권5호
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• pp.1096-1104
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• 2017

This study was carried out to investigate the characteristics of the quality of bread containing Red Ginseng Jung Kwa by-product, added in ratios of 0, 10, 20 and 30% of flour. It was found in dough and bread containing red ginseng Jung Kwa by-product that dough and loaf volume, specific loaf volume, baking loss, and pH decreased with an increasing amount of red ginseng Jung Kwa by-product. In addition, loaf weight and hardness were also reduced. In particular, hardness appeared to be 2.18 times higher for bread containing 30% Red Ginseng Jung Kwa by-product as compared to the amounts found in the control. For color, increasing the amount of Red Ginseng Jung Kwa by-product reduced the L value, whereas the a and b values were increased. In the sensory evaluation, the highest overall preference score was observed in the bread containing 20% red ginseng Jung Kwa by-product, whereas the lowest score was found in the control (no red ginseng Jung Kwa by-product added). It was concluded that pan bread containing red ginseng Jung Kwa by-product could be prepared with good acceptability, and that its optimum concentrate was found to be 20% of flour.

• 정보교육학회논문지
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• 제25권5호
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• pp.683-690
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• 2021

본 연구는 인공지능 교육에 대한 연구 동향을 파악하는 것을 목적으로 2016년 이후 최근까지 발간된 '인공지능 교육'과 관련한 국내학술지논문 164건을 분석하였다. 논문 분석을 위한 준거는 연도별 논문수, 학술지명, 연구 주제, 연구 유형, 자료수집 방법, 연구 대상, 교과로 하였으며 주요 연구 분야와 추후 연구가 필요한 분야를 살펴보고자 하였다. 연구의 방법은 선정한 논문에 대해 주제와 요약을 중심으로 분석하되 불분명한 경우 본문을 확인하였다. 연구의 결과 '인공지능 교육'에 대한 연구는 2017년 이후 본격적으로 시작되었으며 최근 들어 급격하게 증가하는 경향을 보이고 있다. 분석결과 연구 주제에서는 인공지능 교육 프로그램과 콘텐츠 개발, 인공지능의 인식과 이미지에 대한 연구가 많은 편이었다. 연구의 유형에서는 양적연구가 많았고 자료수집 방법으로는 개발 연구 방식이 많이 사용되었다. 연구 대상에서는 초등학교가 비중이 높았으며 교과목에서는 인공지능 내용을 다루는 실과/기술 교과가 많은 것으로 나타났다.

• 생물정신의학
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• 제27권2호
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• pp.42-57
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• 2020

Electroconvulsive therapy (ECT) is indicated for various mental disorders (e.g., major depressive disorder, schizophrenia, and bipolar disorder) and the behavioral and psychological symptoms of dementia in elderly patients. Furthermore, ECT is a useful first-line treatment in emergency and crisis situations such as suicide risk, violent behavior, catatonia, and food refusal, which are more frequent in elderly patients. ECT is also effective in the treatment of the motor symptoms of neurological disorders, such as Parkinson's disease and Huntington's disease. Due to the high risk of various physical diseases, the comorbid physical conditions of elderly patients should be individually controlled to optimize ECT treatment. Compared to young adults, in elderly patients the seizure threshold is higher, the seizure duration is shorter, and the anesthetic dose is lower. On the contrary, the response rate in the elderly is both faster and higher. Considering potential cognitive decline and the prevention of further deterioration of cognitive function in elderly patients, in the absence of significant comorbidities, twice weekly sessions and right unilateral electrode placement with a lower seizure threshold and less cognitive effect are preferred to bilateral electrode placement, which has a high risk of adverse cognitive effects. After an acute course of ECT, continuation and maintenance of ECT, combined with prescription of therapeutic drugs, may prevent possible relapse or recurrence of mental disorders. In conclusion, ECT can be used to treat mental disorders in elderly adults, with safety and effectiveness comparable to that in young adults.

• 한국기계가공학회지
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• 제18권6호
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• pp.45-54
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• 2019

In this study, we analyze the rattle noise of a power takeoff (PTO) driveline and develop a PTO driveline resonance model. We measured the rattle noise of the PTO driveline on the output shaft and, by analyzing the rattle noise in the time domain, we determine that the engine expansion stroke period matches the sound pressure of rattle noise. This finding helped us demonstrate that the rattle noise is caused by the collision between the PTO driving gear and the gear driven by the engine expansion stroke; the torsional vibration caused by this collision is affected by the angular velocity fluctuation of the PTO drive shaft. By measuring the angular velocity of the PTO drive shaft, we confirm that the angular velocity fluctuation of the engine flywheel tends to excessively amplify the PTO drive shaft angular velocity fluctuation. We conclude that the resonance, which occurs when the operating frequency of the engine is close to the natural frequency of the tractor power transmission system, causes the excessive angular velocity fluctuation of the PTO drive shaft. We performed a modal analysis of the PTO driveline resonance and, using the characteristic equation, we show that the resonance occurs when the engine rotation speed is close to 850 rpm, which matches the natural frequency of the PTO driveline.

• 생물정신의학
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• 제27권2호
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• pp.64-73
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• 2020

Suicidality is the most serious complication of mood disorders and psychosis; effective treatment should reduce suicide rates. The Organization for Economic Cooperation and Development age-standardized suicide rate in Korea was 22.6 in 2018, much higher compared to other countries worldwide. As mental and psychiatric problems are the main reasons for suicide attempts, accounting for 31.6% in 2018, targeting such problems should be the focus of efforts to reduce suicide rates. However, the ability of current pharmacotherapeutic and psychotherapeutic interventions to reduce suicide rates is limited due to their delayed effects. Therefore, electroconvulsive therapy (ECT) has been proposed as an alternative treatment. This approach is effective for treating most mental disorders associated with high suicide rates, including severe depression, bipolar disorder, and intractable psychotic disorders; ECT is also effective for Parkinson's disease, which has the highest suicide rate among all disorders in Korea. The acute, long-term, and prophylactic effects of ECT on suicidality have been reported in the literature, and treatment guidelines outside of Korea recommend that ECT be used at an early stage for rapid reduction of suicide rates, as opposed to being applied as a treatment of last resort. However, only ~0.092 of every 10000 members of the Korean general population received ECT in 2018; this is much lower than the average rate worldwide, of 2.2 per 10000. Elimination of obstacles to the use of ECT, early crisis intervention involving administration of ECT for rapid stabilization, and maintenance ECT to prevent recurrence should reduce suicide rates.