Nonlinear Aspects of the Frequency Response of a Gas-filled Bubble Oscillator

김동혁,김정태,이용봉,Kim, Dong-Hyuk,Kim, Jeung-Tae,Lee, Yong-Bong The Acoustical Society of Korea 1991 韓國音響學會誌 Vol.10 No.1

기포 진동 시스템에 대한 수치해석이 수행되었다. 수학적 모델은 기포역학에 대해서는 Keller의 식을, 기포내부 해석을 위해서는 Prosperetti의 식을 채택하였다. Prosperetti는 기포내부 해석을 위해 에너지 방정식을 도입하였으며 매우 정확한 해석을 가능케 하였다. 수치해석결과 기포진동의 주파수 응답곡선에 있어 전형적인 비선형 현상들을 볼 수 있었다. 이러한 비선형 현상들에는 점프현상(jump phenomena), 공진주파수의 변화, 그리고 superharmonic 공진점의 발생등이 있다. 비선형 주파수 응답은 기포진동 시스템의 초기조건에 따라 달라지는데 이에 의해 어느 가진 주파수 대역에서는 두개 이상의 해가 존재할 수 있게 된다. 기포진동 시스템에서 비선형 진동현상은 Duffing 방정식과 비교가 되는데 두 시스템은 비슷한 비선형 현상들을 가지고 있다고 볼 수 있다. A numerical analysis is carried out for the nonlinear phenomena of the bubble oscillator. The model is based on the Keller's formulation for the bubble dynamics. Interpretation of the bubble interior is based on the formulation by Prosperetti. His formulation adopts the energy equation for the analysis of the bubble interior. The numerical simulation Shows typical nonlinear phenomena in its frequency response. Among such nonlinear aspects are the jump phenomenon, the shift of natural frequency of the system, and the appearance of superharmonic resonances. It is deduced that the nonlinear frequency response is dependent upon the initial condition of the bubble oscillator and some multi-valued frequency region can appear in the response curve. Nonlinear phenomena appeared in the bubble oscillator is compared with those of the Duffing equation and it may be said that the bubble dynamic equation has similar nonlinear aspects to the Duffing equation.

재활용 절삭칩으로 제조된 AC2B 합금의 용체화 열처리에 따른 미세조직 및 기계적특성 변화

김동혁,윤종천,최창영,최시근,홍명표,신상윤,예병준,Kim, Dong-Hyuk,Yoon, Jong-Cheon,Choi, Chang-Young,Choi, Si-Geun,Hong, Myoung-Pyo,Shin, Sang-Yoon,Ye, Byung-Joon 한국주조공학회 2018 한국주조공학회지 Vol.38 No.2

Changes in the microstructures and mechanical properties of an AC2B alloy through solution heat treatment were investigated using recycled AC2B cutting chips as raw material. The as-cast microstructure of the AC2B alloy comprised ${\alpha}$-Al, $Al_2Cu$, and coarse needle-shaped phases considered to be eutectic Si and an Al-Fe-Si based intermetallic compound. After solution heat treatments at $505^{\circ}C$ for 1 h and 6 h, the samples showed complete dissolution of $Al_2Cu$ and relatively fine distribution of intermetallic compounds. Hardness test results showed that the hardness rapidly increased after the solution heat treatment for 1 h by solid solution hardening, and the increase of hardness exhibited a plateau from 1 h to 6 h. The results of the hardness and tensile tests showed that there was no visible difference in the effect of 1 h and 6 h solid solution treatment.

웹을 기반으로 한 자기 주도적 MITS -초등 수학 수와 연산 영역 중심-

김동혁,고병오,최의인,Kim, Dong-Hyuk,Goh, Byung-Oh,Choi, Eui-In 한국정보교육학회 2004 정보교육학회논문지 Vol.8 No.3

Recently, there is change the environment of education due to development of Science Technology Specially, As education information on web increased by internet, using education web data by mean of medium that aids learning by computer. Also It studied method that used the Computer as learning medium through the CAI(Computer Assisted Instruction), ICAI(Intelligent CAI), and ITS(Intelligent Tutoring System). But legacy system are not support efficient method that learns to vary learner suitable learning method by individual level. Specially It is not suitable the education course to direct current course of education, and not consider different of student capability, aptitude, need, interesting, not maximized the individual growable power and effect of education. To solve the this problem, our paper suggest the web-based self-directed MITS(Multimedia ITS) that supply the needed the information on web, make the environment that can self-directed learning. To maximized effect of individual learning, our paper structured coursed, characterized, related learning contents in region of numeral at mathematics of primary school. And then integrated contents and class, design and implement the web-based MITS that consist of 4 module to escape from limitation of learner grade, learning time, learning place.

즉결심판제도의 운용 실태에 대한 고찰

김동혁 ( Dong Hyuk Kim ),황순평 ( Soon Pyong Hwang ) 한국경찰법학회 2015 경찰법연구 Vol.13 No.1

Speedy trial are very important values of criminal procedure in terms of finding truth and Due process of law. The constitution guarantees the right to receive the Speedy trial as the fundamental haman rights. Summary judgment actualizes the principle of the Speedy trial. But there is critical opinion that Summary judgment sacrifice other values because of pursuing the Speedy trial. 31) Summary judgment aims at the crime in which an evidence is clear and which the nature of a crime is slight. A prosecutor doesn’t prosecute, and the chief of police station claims a trial to a court directly. The judge of the court can sentence a defendant to the punishment including the fine of under 200,000 wons, detention, or a minor fine. The chief of police station executes the penalty which the judge of the court sentenced. This paper’s purpose solves the practical affairs on trouble which police officers in charge of Summary judgment have experienced. So, I implemented questionnaire study about them, and I arranged and opend that results and analyzed the results of survey and presented substantial solutions. Survey is as follows. The maintenance or abolition of Summary judgment(1), Who should exercise the right of prosecution of Summary judgment(2), Subject of Summary judgment(3 to 5), The abuse of the rignt of prosecution of Summary judgment(6), The absence of the defendant and method of the trial(7 to 10). I wish this paper contributes to the operating system and that the unity of summary conviction.

A PRAYER FOR GOD’S PEOPLE (SIRACH 36:1-22): THE PROBLEM OF AUTHENTICITY

KIM Dong-Hyuk(김동혁) 장로회신학대학교 기독교사상과 문화연구원 2019 장신논단 Vol.51 No.4

벤 시라의 지혜서 속 “하나님의 백성을 위한 기도”(집회 36:1-22)는 책의 나머지 부분과 여러모로 대비된다. 이 때문에 많은 학자는 이 기도문이 벤 시라 자신이 직접 쓴 것이 아니라 다른 저자가 마카베오 시대에 써서 삽입한 것으로 본다. 반면, 일군의 학자들은 이 기도문이 비록 집회서 초고가 완성된 이후에 삽입되긴 했으나 벤 시라 자신이 직접 쓴 것이라고 주장한다. 본 연구는 이 기도문이 집회서의 저자인 벤 시라가 쓴 것인지 아닌지 답하려는 데에 그 목적이 있다. 이를 위해 먼저 학자들이 기도문의 시대적 배경으로 제안하는 두 시기를 논의하는데, 이 중 한 시기는 벤 시라의 저작설을 지지하는 이들이 제안하는 시기이고 다른 한 시기는 벤 시라의 저작설을 받아들이지 않는 이들이 제안하는 시기이다. 그 다음, 논문은 기도문의 사상, 형태, 언어, 주제를 탐구하고, 그것들을 책의 나머지 부분과 비교한다. 첫째, 사상과 관련하여, 하나님이 여러 민족들을 심판하신다는 사상은 책의 나머지 부분에서 만나는 관련된 다른 사상들과 양립하기 힘들다. 둘째, 집회서 속 다른 기도문들과 비교할 때 이 기도문은 그 형태가 화자의 수(단수/복수), 하나님을 부르는 방식, 목적에 있어서 독특하다. 셋째, 기도문 속에서 qṣ와 mw‘d는 묵시적 의미를 띠는데, 두 단어의 이러한 용법은 두 단어가 집회서의 다른 부분에서 사용된 방식과 확연하게 다르다. 넷째, 기도문에서 중요하게 나타나는 주제들, 예컨대 성서 속 예언의 실현과 출애굽에 대한 암시 역시 집회서의 다른 곳에서는 발견되지 않는다. 결론적으로, “하나님의 백성을 위한 기도”(집회 36:1-22)는 벤 시라가 쓰지 않았으며 다른 사람이 아마도 마카베오 시대에 삽입했다고 이해하는 것이 타당하다. The Prayer for God’s People in the Wisdom of Ben Sira (36:1-22) shows many features that are distinct from the rest of the book, and its uniqueness has led many scholars to reject its authenticity and to situate the passage into the Maccabean period. On the other hand, some other scholars defend its authenticity, arguing that the prayer was written by Ben Sira himself, though inserted into an already finished draft. The purpose of this paper is to answer the question whether the prayer was composed by the author of the Wisdom. The paper begins by discussing the two proposed settings for the prayer, one argued by those who accept the prayer’s authenticity and another argued by those who reject it. It then examines the idea, form, language, and themes of the prayer and compare them with those of the rest of the book. First, the idea of the divine judgment upon the nations is shown to be hardly compatible with the related ideas in the rest of the book. Second, the form of the prayer, when compared with other prayers in the book, also underlines the prayer’s uniqueness with regard to the number of the speaker, the designation of the Deity, and the purpose. Third, the meaning of qṣ and mw‘d in the prayer, which is clearly apocalyptic, cannot be reconciled with the use of the same words in the rest of the book. Last, some important themes in the prayer are not found elsewhere in the book, for example, the actualization of biblical prophecy and the allusion to the exodus tradition. All these observations suggest that the Prayer for God’s People (Sir 36:1-22) cannot have been composed by Ben Sira and that it was inserted by another hand probably during the Maccabean period.

적소이론을 통해 본 도서 발견에 관한 연구

김동혁(Kim Dong Hyuk),한주리(Han Julie) 한국출판학회 2018 한국출판학연구 Vol.44 No.2

본 연구는 수많은 콘텐츠가 범람하는 상황에서 미디어를 통한 ‘도서 발견’이 어떻게 나타나는지 살펴보고자 하였다. 매년 출간종수는 늘어나지만, 무수히 넘쳐나는 콘텐츠로 정작 독자는 도서가 있다는 것을 ‘알게 되거나’, ‘인지’하는 것은 쉽지 않다. 때문에 독자에게 도서를 발견할 수 있도록 만들어줄 필요성이 제기되고 있다. 이에 본 연구는 우연한 도서 발견과 관련하여 전통미디어인 TV와 신문, 소셜미디어인 페이스북과 인스타그램의 경쟁관계를 충족적소분석을 통해 살펴보았다. 미디어 충족요인은 정보추구, 재미ㆍ오락, 시간보내기로 구분하였으며 이에 따른 우연한 도서 발견의 경험을 살펴보았다. 미디어 간의 적소분석을 진행한 결과 우연한 도서 발견의 적소폭은 페이스북, TV, 인스타그램, 신문 순으로 나타났다. 적소중복에서는 페이스북과 인스타그램이 모든 충족차원에서 강한 경쟁관계를 보였으며, 경쟁적 우위는 페이스북, 인스타그램, TV, 신문 순으로 경쟁력을 가진 것으로 나타났다. 이를 통해 도서 발견에 있어 미디어 채널의 흐름이 전통미디어에서 소셜미디어로 이행되고 있음을 확인하였다. The purpose of this study is to investigate how ‘book discovery?’ occurs through the media through numerous contents in various situations. Reader can obtain information on books through media channels. But it is not easy for readers to ‘know’ or ’recognize’ the book’s existence. Therefore, there is a need to make the book discoverable to the reader. In this respect, this study examines the controversy of accidental book discovery through gratification niche theory, which compares the old media, TV, newspapers, and social media, Facebook and Instagram. Media usage gratifications was categorized as information seeking, fun & entertainment, and time spent. As for the serendipity book discovery, the result of analyzing the proper place among the media showed that the niche breadth was in Facebook, TV, Instagram, and newspaper respectively. On the other hand, Facebook and Instagram showed strong competition in all dimensions, and competitive superiority was shown to favor in the order of Facebook, Instagram, TV, and newspapers. This study confirms that social media has a competitive superiority over the old media such as TV and newspapers, in regards to readers accidentally discovering books. In the discovery of books, the current of media is shifting from old media to social media.

아세라 기둥, 아세라 여신?

김동혁(Dong-Hyuk Kim) 대한성서공회 2013 성경원문연구 Vol.- No.32

에스겔 비유의 알레고리적 해석 연습

김동혁(Dong-Hyuk Kim) 한국신학정보연구원 2014 Canon&Culture Vol.8 No.1

본 소고는 성경 해석에 있어 알레고리적 해석이란 무엇이며, 그 공헌과 한계는 무엇인가 하는 질문에 답하기 위한 시도이다. 논의는 다음과 같이 진행된다. 첫째, 성서학의 맥락 속에서 알레고리를 정의한다. 이때 알레고리와 연결점이 있는 다른 문학적 기법들도 살펴본다. 둘째, 알레고리적 성경 해석을 대표하는 3세기 신학자 오리게네스의 알레고리적 성경 해석의 원리를 논의한다. 셋째, 에스겔이 말한 알레고리의 실례인 ‘부정한 아내 예루살렘’의 알레고리(겔 16장)의 일부를 간략히 살핀다. 넷째, 알레고리적 성경 해석의 실례로서 에스겔 16장의 알레고리의 일부에 대한 오리게네스의 해석을 요약한다. 결론 부분은 알레고리적 성경 해석의 공헌과 한계를 간략히 논의한다. The present study is a case study in attempting to answer the following questions with regard to the allegorical reading of the Bible: what is allegorical reading in biblical hermeneutics, and what are its contributions and limitations? The study proceeds as follows. First, we define allegory in the context of biblical studies, while paying attention to its differences from other literary devices such as simile, metaphor, fable, parable, and typology. Second, as a representing figure of allegorical interpretation, we examine the principles of Origen’s allegorical reading of the Bible. Third, as a biblical example, we look at a part of Ezekiel 16, which is the allegory of The Adulterous Wife Jerusalem. Fourth, as a case study, we survey Origen’s interpretation of the part of the aforementioned allegory in Ezekiel 16. As a conclusion, we briefly discuss the contributions and limitations of the allegorical interpretation of biblical texts.

역정규 손실함수를 이용한 기대손실 관리도의 설계

김동혁(Kim Dong-Hyuk),정영배(Chung Young-Bae) 한국산업경영시스템학회 2015 한국산업경영시스템학회 학술대회 Vol.2015 No.추계

Control chart is a graph of plotting dot in the process characteristic values. It is a statistical technique that can be known whether or not the in-control state in this step. In many companies have use as a statistical process control(SPC) tool. Control chart is the management process quality characteristic value, which is plotted dot is whether the existence within the control limits. But, this is not given information about the economic loss that occurs when a product is produced characteristic value does not match the target value of the process. In that sence, expected loss control chart(EL control chart) is very effective process control tool. Because it is a process control chart in consideration to economic loss. The EL control chart is using the quadratic loss function of Taguchi. However, Taguchi’s quadratic loss function is simple quadratic curve. It is difficult to realistically reflect the increased amount of loss that due to a deviation from the target value. In this paper, we design a new control chart using the reflected normal loss function(RNLF). And we demonstrate its effectiveness by using the control chart performance comparison of EL control chart.

매실음료 섭취가 대학축구선수의 심혈관계 및 피로도에 미치는 영향

김동혁(Kim, Dong-Hyuk),김규태(Kim, Kyu-Tae),이강구(Lee, Kang-Koo) 한국체육과학회 2015 한국체육과학회지 Vol.24 No.3

This research was compared and analyzed about University soccer players’s cardiovascular activity and fatigability after they did graded maximum exercise because of drinking water and plum concentrate. There is purpose to make a great contribution their ability of improving exercise, and this research is going to help their ability of exercise performance and fatigue recovery. I selected soccer players who have done athletics for over seven years and they have to do athletics for twenty hours everyday with identical food composition. The soccer players who participated for research are student of S University in Wonju. They implemented twice, so I separated that the players drink water first than plum concentrate. I got conclusion after I have analyzed their alteration of heart rate, anaerobic threshold, hypertension, oxygen consumption, lactic acid and training. First, conclusion of maximum heart rate and normal heart rate are not really different in players who drink water(group W) and players who drink plum concentrate(group P), but group P of heart rate are lower than before. Second, conclusion of hypertension has two difference that are normal hypertension contraction and the first hypertension contraction(p〈.05). However hypertension relaxation when the players calm, first hypertension relaxation, second hypertension contraction and second hypertension relaxation are not different at all about group W and group P. Third, conclusion of oxygen consumption is not different about maximum oxygen consumption about group W and group P. Fourth, conclusion of anaerobic threshold is not different about group W and group P. Fifth, conclusion of lactic acid has difference between normal lactic acid and maximum lactic acid(p〈.05) but I can not find any difference in two groups after 10min, 30min and 60min. Sixth, conclusion of training time is different in group W and group P about the time. In final research, the soccer player did graded maximum exercise after they drank plum concentrate that is not effective in overcoming fatigue. However, this is positive effect about exercise ability and continuous time of exercise if the players train everyday with plum concentrate.