A High-Efficient Transformer Using Bond Wires for Si RF IC

CHO, Eunil,LEE, Sungho,LEE, Jaejun,NAM, Sangwook The Institute of Electronics, Information and Comm 2010 IEICE transactions on electronics Vol.93 No.1

<P>This paper presents a design of a monolithic transformer using bond wires. The proposed transformer structure has several advantages such as high power handling and high efficiency. It shows that the measured insertion loss at the 1.9GHz range is -1.54dB (70%), which is higher than the spiral transformer of the same size. Also, it shows a phase error of less than 1 degree.</P>

Methane Production of Food Waste Anaerobic Digestion Recovered from NaCl Inhibition by Water Dilution

( Eunil Cho ),( Qiyong Xu ),( Danling Xia ),( Jae Hac Ko ) 한국폐기물자원순환학회 2021 한국폐기물자원순환학회지 Vol.38 No.4

One of the significant challenges of food waste anaerobic digestion (AD) is the negative effect of high NaCl concentrations. This study investigated the effects of NaCl fluctuation on the methane generation of food waste AD under thermophilic and mesophilic conditions. Particularly, the effects of the shock loading of high NaCl concentration with/ without water dilution treatment were investigated. Generally, the methane generation decreased with increasing NaCl concentration. In addition, the sensitivity of the thermophilic AD to NaCl concentrations (5-10 g/L) was higher than that of the mesophilic AD. Furthermore, with an increase in the NaCl concentration from 0 to 30 g/L, the accumulative methane volumes of the thermophilic reactors decreased from 210 to 45 mL/gVS, and those of the mesophilic reactors decreased from 265 to 67 mL/gVS. Additionally, the pH of digestate decreased with increasing NaCl concentration. In contrast, the concentrations of the chemical oxygen demand and volatile fatty acid increased with increasing NaCl concentration. These results indicated that a shock loading of NaCl significantly reduced methane generation. In addition, the methane generation rates could be recovered up to 64-72% using water dilution as a remedial measure. Further investigation using 16S rRNA analysis revealed that the predominant genus of the methanogens shifted from Methanoculleus to Methanosarcina after the removal of the osmotic stress using water dilution.

An efficient CMOS power-combining technique with differential and single-ended power amplifier

Cho, Eunil,Song, Yonghoon,Lee, Sungho,Park, Joontae,Nam, Sangwook Wiley Subscription Services, Inc., A Wiley Company 2010 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.52 No.10

<P>This article proposes an efficient power-combining architecture with differential and single-ended power amplifiers (PAs) in a CMOS process. The single-ended amplifier is added for overall efficiency enhancement. To demonstrate this concept, a CMOS PA using the proposed architecture was fabricated with a 0.13-μm CMOS technology that delivers 30.6 dBm of output power with 42% drain efficiency and 38% power-added efficiency at 1.95 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2214–2217, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25460</P>

Regional Security Order and South Korea-Japan Relations

( Eunil Cho ) 한국국방연구원 2022 The Korean Journal of Defense Analysis Vol.34 No.4

This preliminary study focuses on the change in the regional security order caused by the U.S.-China competition and its impact on South Korea-Japan relations. The ongoing U.S.-China relations has expanded beyond the discussion of cooperation and competition between existing and emerging powers, as well as the debate over the influence and resilience of the U.S.-led liberal international order. The significance of the U.S.-China competition in the security order in East Asia depends on whether China will accept the existing U.S.-led bilateral alliance system and take a status quo attitude. As a result, the U.S. allies, South Korea and Japan, need to respond sensitively to the changing nature of the security order. In this vein, this study explains the East Asian security order as elements of power structure, institutions, and actors. In addition, it explains the emergence of China as a new hegemonic power due to the U.S.-China competition, the hub-and-spokes system changes according to the U.S. rebalancing policy, and the emergence of Trumpism. Through this, the author argues two claims. First, the change in U.S.-China relations has led to different expectations between Seoul and Tokyo for cooperation with the U.S., which has hindered bilateral cooperation between them. Second, divergent views on China also hinder South Korea-Japan cooperation. Through the Senkaku dispute between Japan and China and the missile deployment dispute between South Korea and China, the two countries later showed different directions in their policy toward China. In the current competitive situation, restrictions on South Korea-Japan relations are inevitable. However, if the opportunity to promote security cooperation between South Korea and Japan is sought, it will be able to show the cooperation of middle power countries that can develop the security order to mitigate the intensity of U.S.-China competition.

일본 아베 정권의 대북정책: 현황과 전망

조은일 ( Cho Eunil ) 한일군사문화학회 2019 한일군사문화연구 Vol.27 No.-

향후 일본 아베 정권의 대북정책은 변화할 것인가. 본고는 2차 아베 정권의 대북정책의 현황을 진단하고 향후 어떻게 변화할 것인지 전망하는 데 목적이 있다. 아베 정권의 대북정책에 변화의 조짐이 보이기 시작한 것은 2018년 6월 싱가포르 선언 이후 남북미 관계가 한반도 비핵화 및 평화체제 구축을 위한 긍정적 방향으로 움직이면서부터다. 아베 정권은 거시적으로는 미국의 대북정책의 틀에서 북한 비핵화 문제의 해결을 모색하고 있으며, 미시적으로는 남북관계 진전 정도를 관찰하면서 북한과의 대화 가능성을 탐색하고자 한다. 아베 정권의 대북정책은 국교정상화, 북한 핵·미사일 문제, 일본인 납치문제 등의 세 이슈가 포괄적으로 연계되어 있다. 즉, 일본은 북한 핵·미사일 문제와 납치문제가 포괄적으로 해결되면 북일간 국교정상화 협의가 진전될 것이라는 도식을 가지고 있기 때문에 급변하는 대외 환경에서도 매우 천천히 변화하는 경향을 보이고 있다. 이러한 배경에서 한반도 비핵화 및 평화체제가 지속적으로 추진되더라도 아베 정권은 북한의 완전한 비핵화가 이루어지기 전까지 대북제재를 강화하는 압력을 지속하고자 한다. 나아가 미국이 인도·태평양 전략을 내세우면서 중국과의 전략적 경쟁을 주도하는 과정에서 지역 안보정세는 불안정한 과도기적 상황에 놓여있다. 이러한 상황에서 일본은 북한의 완전한 비핵화를 유인하기 위해 미국의 대한반도 영향력이 약화되어서는 안된다고 본다. 따라서 아베 정권은 미국이 대북 관여 가능성을 열고 있는 상황에 유념하여 적극적인 정책 변화를 모색해야 할 시점에 와있다. 2002년 북일 정상회담이 북일관계의 새로운 협력의 전기를 마련했던 것처럼, 아베 정권은 북한과의 대화를 모색하면서 관계변화를 추구하는 것이 바람직할 것이다. Will the Abe administration’s North Korea policy change? The purpose of this paper is to examine the current status of Abe administration’s policy toward North Korea and to forecast how it will change in the future. The Abe administration’s North Korea policy began to change after the Singapore summit between the U.S. President Donald Trump and North Korean leader Kim Jong Un in June 2018, as the relationship among South Korea, the U.S. and North Korea moved toward a positive direction for the denuclearization of the Korean peninsula and the establishment of the peace regime. The Abe administration is broadly seeking to solve the denuclearization issue in the framework of the U.S. policy toward North Korea, and specifically looking at the possibility of dialogue with North Korea in tandem with the change of inter-Korean relations. Japan’s North Korea policy is intertwined with normalization, North Korean nuclear and missile threats, and abduction of Japanese citizens. In other words, Japan has a tendency to change very slowly even in a rapidly changing external environment because it has a scheme that Japan-North Korea normalization will advance if both North Korea’s nuclear and missile issues and abduction issues are resolved in a comprehensive manner. In this context, even if the denuclearization of the Korean peninsula and the peace regime continue, the Abe administration intends to continue the pressure to strengthen sanctions by the international community until the complete denuclearization of North Korea is achieved. In addition, the U.S. is promoting the Indo-Pacific strategy in the midst of the regional instability in the process of leading the strategic competition with China. In this situation, Japan does not think that the U.S. should be weakened to influence the regional stability in order to fully induce complete denuclearization of North Korea. Therefore, the Abe administration should look for positive policy changes, keeping in mind the U.S. engagement with North Korea. As Japan-North Korea summit in 2002 provided the new cooperation between the two, it would be better for the Abe administration to pursue a policy change toward North Korea while seeking dialogue with it.

근육 부피 변화에 따른 손동작 분류 알고리즘을 기반으로 한 HCI 시스템의 개발

조은일(Eunil Cho),허정현(Jung Hyun Heo),이정직(Jeongjick Lee),윤영로(Young Ro Yoon) 대한인간공학회 2016 대한인간공학회 학술대회논문집 Vol.2016 No.11

Objective: The aim of this study is to propose alternative method about sensing muscle activity to classify hand gesture. When human act hand gesture, muscles will be contracted or relaxed. So we use ‘Conductive Rubber Cord’ to measure muscle volume change. Background: Different hand gesture shows different muscle volume change. And about same hand gesture shows very similar muscle volume change. Method: We determine 5 kinds of hand gestures and measure muscle volume change. So we suggest a parameter based on muscle volume change measured by conductive rubber cord. The work is based on two facts. One is that hand gesture or motion is controlled by fore arm and the other is that volume change of forearm occurs by doing hand motion. Based on these facts, we assume that a variety of hand gesture results in various volume change of forearm case by case. Results: The sensitivity of the classification used for the 5 kinds of hand gestures was 96.39%. Conclusion: Muscle volume change is not affected by electric signal or feature of human body. So it didn’t need preprocessing for separate parameter from undesirable signals. This means Muscle volume change is more useful than sEMG or other bio signal. Application: The results of this study might help to determine alternative method about sensing muscle activity. And it can be applied to develop controller for virtual-reality system.

Effects of Feedforward in In-Air Remote Pointing

Cho, Kwangsu,Lee, Ju-Hwan,Lee, Byeong-Taek,Park, Eunil Taylor Francis 2015 INTERNATIONAL JOURNAL OF HUMAN-COMPUTER INTERACTIO Vol.31 No.2

Comprehensive Approaches to User Acceptance of Internet of Things in a Smart Home Environment

Park, Eunil,Cho, Yongwoo,Han, Jinyoung,Kwon, Sang Jib IEEE 2017 IEEE Internet of things journal Vol.4 No.6

<P>With rapid improvements in communication technologies and infrastructure, the Internet of Things (IoT) has become a promising sector within the global information and communication technology industry. Various fields are employing the concept of IoT for their traditional products and services for convenient use by consumers. In the construction industry, the majority of leading companies and organizations are using IoT technologies in a smart home environment. However, only few studies have focused on the user experience of IoT technologies in such an environment. Thus, the current study explores the key determinants of user acceptance of IoT technologies in a smart home environment, and investigates a research model integrated with five potential user factors and a technology acceptance model. The results of the collected data, which were investigated using a structural equation modeling method, show that three positive motivations, compatibility, connectedness, and control, and a negative hindrance, cost, are significant determinants of the technology acceptance behavior of users. The current study can serve as a foundation for future studies on improving IoT technologies in a smart home environment by considering the user experience.</P>

터치스크린과 전자펜의 실용화에 대한 접근 : 문서작성에서의 사용성 평가

박은일(Eunil Park),조광수(Kwangsu Cho) 한국HCI학회 2011 한국HCI학회 학술대회 Vol.2011 No.1

Reading experiences influencing the acceptance of e-book devices

Park, Eunil,Sung, Jungyeon,Cho, Kwangsu Emerald Group Publishing Limited 2015 The Electronic library Vol.33 No.1

<P><B>Purpose</B></P> <P> – This paper aims to explore users’ perception of, and then intention toward using, e-book devices as new reading devices, based upon an integrated technology acceptance model (TAM), reading engagement based upon flow theory and readability. The recent introduction of e-book devices has drastically changed the way people access and use reading content. However, few studies have explored the impact of reading experience on acceptance of e-book devices. </P> <P><B>Design/methodology/approach</B></P> <P> – A total of 219 participants participated in a survey after using e-book devices to analyze the research model. </P> <P><B>Findings</B></P> <P> – This study confirmed the crucial roles played by viewing experience, perceived mobility, perceived behavioral control, skill and readability. Also perceived usefulness and text satisfaction were found to have a positive and significant association with acceptance of e-book devices. </P> <P><B>Research limitations/implications</B></P> <P> – Implications and suggestions for researchers and manufacturers are also addressed in the present study. </P> <P><B>Originality/value</B></P> <P> – The current study focused on how actual reading experiences using e-book devices influences acceptance of e-book devices, through the triangular integrated model of TAM, reading engagement and readability features, and investigating users’ reading experience on the basis of responses to the characteristics of e-book devices.</P>