0.36Mn이 함유된 구상흑연주철의 냉각조건에 따른 기계적 거동 고찰

김석동,김성규,Kim, Suck-Dong,Kim, Sung-Gyoo 한국주조공학회 2021 한국주조공학회지 Vol.41 No.4

Effects of cooling condition after solidification on the microstructure and the mechanical properties of 0.36Mn containing ductile cast iron have been studied based on the minimized addition of Cu and Sn for vehicle component applications with better quality and cost competitiveness. Cu and Sn were selected for additional elements judging from the well-known fact of strong tendency of pearlite promotion followed by the tensile property improvement. After pouring of the Mg treated cast iron melt with various chemical compositions into the block specimens, two ways of post solidification cooling conditions were applied for comparison; both cooling in the mold and cooling in the air after dismantle at 800℃. The pearlite fraction of the mold-cooled specimens was analyzed as 27-44%, with the tensile strength and elongation of 513-568N/mm² and 10.4-14.3%, respectively. Whilest, the air cooled specimens showed the pearlite fraction of 77~85%, with the tensile strength and elongation of 728~758N/mm² and 3.2~6.0%, respectively. It is worthwhile to note that the remarkable improvement of both tensile strength and elongation of the ductile iron was achieved by the present air cooling condition with the minimized combined addition of Cu and Sn to the 0.36Mn containing ductile iron. 우수한 기계적 성질과 가격경쟁력을 갖는 구상흑연주철 합금 개발을 위해 Cu와 Sn을 소량 첨가한 고 Mn 구상흑연주철의 응고 후 냉각조건에 따른 미세조직과 기계적 특성을 분석하였다. 첨가원소인 Cu와 Sn의 경우 펄라이트 형성 촉진을 통한 인장특성 향상을 위해 선택하였다. 또한 물성에 미치는 냉각속도의 영향을 확인하기 위해, Mg 처리된 다양한 조성의 합금을 블록시편에 주입한 후 주형 내 냉각과 800℃에서 주형 해체 후 공랭의 두 가지 냉각 조건을 비교분석하였다. 주형 내 냉각 시편의 경우, 펄라이트 분율은 27-44%, 인장강도와 연신율은 각각 513-568N/mm²와 10.4-14.3%로 나타났다. 반면, 이른 형해체 공랭 시편의 경우에는 펄라이트 분율은 77~85%, 인장강도와 연신율은 각각 728~758N/mm²와 3.2~6.0% 이었다. 결론적으로, 소량의 Cu 및 Sn 함유 Mn 구상흑연주철의 공랭 시 괄목할만한 인장강도와 연신율의 증가를 확인할 수 있었다.

학회순례 - 창립 40돌 농업발전에 크게 기여 "한국작물학회"

김석동,Kim, Seok-Dong 한국과학기술단체총연합회 2002 과학과 기술 Vol.35 No.7

추파대맥 (秋播大麥) 재배시 기비로 (基肥) 시용한 (施用) 요소의 (尿素) 질산화 및 그에 따른 질산태질소의 (窒酸態窒素) 환경에의 방출

김석동,소창호,권용웅,임웅규 ( Sok Dong Kim,Chang Ho Soh,Yong Woong Kwon,Ung Kyu Lim ) 한국환경농학회 1993 한국환경농학회지 Vol.12 No.2

The use of fertilizer N is essential for maximum economic yield of crops. Meanwhile, enrichment of NO₃^-in the environment has to be avoided. Winter barley crop has a short duration of growth before winter, but is used to receive N greater than 60 ㎏/㏊ at seeding. Experiments were performed to determine the quantitative aspect of the fate of soil applied urea N among the residual, leached, and uptaken by winter barley (cv. Olbori), and to evaluate the effect of soil temperature on nitrification. Four levels of urea (0, 40, 80, and 120 ㎏ N/ha) was basal-dressed to Olbori. NH₄^- appeared dominant in the soil until 40 days after seeding, whereas NO₃^- did thereafter. Nitrification rate at 5°C of soil temperature was 40 to 50% of that at 15 ℃. Linear increases in the number of ammonia oxidizing and nitrite oxidizing bacteria of the soil was present as the level of urea fertilization was higher. Less than 60% of N applied at seeding was uptaken by winter barley until mid-March but 50% was lost from death of older barley leaves during overwintering. Thereby only 10% of the applied N remained in the barley in spring. Only 15% of the applied N was present in the rhizosphere. The 17 to 20% of the soil applied N leached out as NO₃^- the rhizosphere. Nitrogen leaching during winter was estimated to be 16 and 20 ㎏/㏊ when the basal application level of urea fertilization was 80 and 120 ㎏/㏊, respectively.

신경망을 이용한 우리말 음성의 인식에 관한 연구 - 복합 신경망을 이용한 초성자음 인식에 관한 연구

김석동,이행세,Kim, Suk-Dong,Lee, Haing-Sei 한국음향학회 1992 韓國音響學會誌 Vol.11 No.3

본 논문은 신경망을 이용한 자음인히기에 관한 연구이다. 우선 자음과 모음이 포함된 음성에서 자음부분을 분리하였다. 각각의 자음을 몇개의 집단으로 나누어서 자음구간대 영교차율을 조사하였다. 마지막으로 자음을 인식하기 위해 제어망과 몇개의 소규모 망으로 구성한 혼합 신경망을 제안한다. 제어망은 입력된 자음이 어느 집단에 속하는가를 결정하고, 소규모망에서는 각 집단에 속하는 자음을 인식한다. This paper is a study on the consonant recognition using neural network. First, the part of consonant was separated from the sound of vowel and consonant by the use of acoustic parameter. The rate of length vs. zero crossing rate in the sound of consonant had been studied by dividing each consonant into several groups. Finally, for the purpose of consonant recognition, the composite neural network which consists of a control network and several sub-network is proposed. The control network identifies the group to which the input consonant belongs and the sub-network recognizes the consonant in each group.

도협칼럼 - 문화와 공공도서관

김석동,Kim, Seok-Dong 한국도서관협회 2000 圖協會報 Vol.41 No.6

율무 박피 다수성 선발 계통의 생육 및 종실특성

이정일(Jung Il Lee),박장환(Jang Hwan Park),김석동(Sok Dong Kim),안병옥(Byeong Ok Ahn),이승택(Seung Tack Lee) 한국약용작물학회 1993 한국약용작물학회지 Vol.1 No.1

This study was conducted to select thin-shelled and high-yielding lines in job`s-tears. Two breeding lines of Suwon 3 and Suwon 6 were selected from the local collections. These two lines were tested and investigated on their characteristics under the field condition. The heading date of Suwon 3 and Suwon 6 was later one or two days, but the maturity date was one or two days earlier than that of check variety Kim-jejong, respectively. The number of grains per hill of Suwon 3, Suwon 6 was 50%, 49% greater and the milling rate was 3.8%, 5.6% higher than that of check variety, respectively. Althought 1000 grain weight of Suwon 3 and Suwon 6 was 20g lighter and the rate of ripeness was 6%, 12% lower, the raw grain yield was 22%, 20% higher than that of check variety, respectively. The thickness of seed coat of Suwon 3 and Suwon 6 was thiner and the hardness of seed coat was lower than that of check variety, therefore the milling time was decreased 12%, 7% compare to check variety, respectively. The crude protein contents of Suwon 3 and Suwon 6 was slightly higher and the amino acid composition of Suwon 6 was similar to Kimjejong, but Suwon 3 was lower than that of check variety.

고속철도 뜬침목 발생량에 대한 정량적 연구

김석동(Kim Suk-Dong),박용걸(Park Yong-Gul),김대상(Kim Dae-Sang),김학균(Kim Hark-Kyun) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-

Floating sleepers in a ballasted track increase both track deterioration and track irregularities. Consequently, a considerable maintenance work is required and maintenance cycle is shortened due to the floating sleepers. This paper quantifies the degrees of void between the floating sleepers and a ballast bed. In the future, the influence of floating sleepers on the track will be investigated by an analytical method using a dynamic model.

자갈궤도 뜬침목 간이 평가 방법

김대상(Kim Dae Sang),김현기(Kim Hyun Ki),이태균(Lee Tae Gyun),김석동(Kim Seok Dong),김성중(Kim Sung Jung) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-

Hanging sleepers, which are not fully supported between the sleepers and the ballast, could cause large dynamic forces especially on high speed ballasted track. The dynamic forces resulting from insufficient supporting forces may badly affect the running stability and safety of train. These also accelerate track irregularities and deteriorate track components rapidly. Consequently, thehanging sleepers will lead to sharp increases in track maintenance cost. This paper introduces a rapid and easy method to detect hanging sleepers with portable light falling weight deflectometer (LFWD) and summarizes the results of experiments performed at the high speed ballasted track.

Conservative Corporatism of Developmental States: One Common Outcome of Low Inequality Between Conservative and Social Democratic Corporatism

김석동 ( Seokdong Kim ) 한국행정학회 2022 한국행정학회 학술발표논문집 Vol.2022 No.2

My research provides a conceptualization of conservative corporatism compared to social democratic corporatism and, by extension, proposes a typology of the developmental state compared to the welfare state. Developmental states, such as Japan, South Korea, and Taiwan, maintained low inequality in the long term during rapid industrialization despite weak welfare regimes and low social expenditures. Why have both East Asian developmental states and European corporatist states commonly maintained long-term low inequality despite their contrasting ideologies of conservativism versus social democracy respectively? Developmental states have created state-led asymmetric coordination with firms but without labor. Both conservative corporatism and social democratic corporatism differ in the formation of the conservative welfare state and the social democratic welfare state respectively, but both have commonly maintained long-term low inequality. Developmental states’ conservative corporatism maintained egalitarianism with progressive land reforms, near-full employment, and educational improvement despite the absence of institutionalized welfare regimes. Social democratic corporatism can promote the state’s inclusiveness by sustaining a broad consensus between classes and, by extension, provide a roadmap for the inclusive state to realize economic democratization and to overcome inequality caused by the COVID-19 pandemic.

국제 음소의 자동 생성을 활용한 연속음성인식에 관한 연구

김석동(Kim, Suk-Dong),홍성수(Hong, Seong-Soo),신좌철(Shin, Chwa-Cheul),우인성(Woo, In-Sung),강흥순(Kang, Heung-Soon) 한국게임학회 2007 한국게임학회 논문지 Vol.7 No.2

자동 음성 인식(Automatic Speech Recognition)기술은 세계적인 의사소통과 협력을 원활히 할 수 있는 가능성을 제시한다. 현재까지 대부분의 연구들은 주로 사용되는 단일 언어의 말하기에만 집중되어 있다. 따라서 다른 언어들과 함께 사용되는 특정 ASR 시스템을 도입하는 데에는 비싼 비용이 뒤따른다. 본 논문은 다국어 음성 인식에 대한 일반적 접근으로 각 나라 언어를 대표한 발음사전(어휘모델)을 만들기 위하여 음성 인식에 이용하는 어휘 모델을 만들기 위하여 음소 언어 인식(PLI, Phonetic Language Identity) 형식의 입력된 파일을 해석하는 국제 음소 엔진(IPE, International Phoneticizing Engine)를 제안한다. IPE는 독립적이며 규칙을 기본으로 한다. 어휘모델 생성 과정은 Java 언어로 구현된 프로그램에 의해 이루어지고, 이 과정들은 규칙 상충을 줄여주며, 언어학적 훈련을 받지 않은 사람의 규칙 생성도 가능하게 한다. IPE에 의해 생성된 어휘모델을 연속 음성 인식기에 적용한 결과 우리말 인식률이 92.55%, 영어에 대하여 89.93%를 얻었다. One result of the trend towards globalization is an increased number of projects that focus on natural language processing. Automatic speech recognition (ASR) technologies, for example, hold great promise in facilitating global communications and collaborations. Unfortunately, to date, most research projects focus on single widely spoken languages. Therefore, the cost to adapt a particular ASR tool for use with other languages is often prohibitive. This work takes a more general approach. We propose an International Phoneticizing Engine (IPE) that interprets input files supplied in our Phonetic Language Identity (PLI) format to build a dictionary. IPE is language independent and rule based. It operates by decomposing the dictionary creation process into a set of well-defined steps. These steps reduce rule conflicts, allow for rule creation by people without linguistics training, and optimize run-time efficiency. Dictionaries created by the IPE can be used with the speech recognition system. IPE defines an easy-to-use systematic approach that can obtained 92.55% for the recognition rate of Korean speech and 89.93% for English.