Analysis of the Motion of a Harmonic Oscillator Coupled to Faraday's Law

KIM*, Se-Hun,KO, Tae-Eon,LEE, Se-Hyun,KIM, Kwang-Sun,OH, Seung-Won,KIM, Hyun-Seok Korean Physical Society 2018 새물리 Vol.68 No.1

어포던스 개념과 게슈탈트 심리학의 연관성 고찰 - 디자인 조형의 관점에서 -

오세헌(주저자) ( Oh¸ Sehun(주저자) ),오세헌(교신저자) ( Oh¸ Sehun(교신저자) ) 디자인융복합학회(구.한국인포디자인학회) 2021 디자인융복합연구 Vol.20 No.1

게슈탈트와 어포던스 개념은 디자인 분야에서 대표적으로 접하는 심리학 관련 용어로 모두 시지각과 관련된 심리학 연구에서 출발했으나, 그동안 둘 사이의 연관성이 특별히 주목받지 못하여 개별적으로 연구되어왔다. 본 연구에서는 어포던스 용어를 만든 깁슨이 개념의 출발점으로 게슈탈트 심리학자들의 개념을 언급하고 있다는 사실을 바탕으로, 문헌 연구를 통해 게슈탈트 심리학자들의 디맨드 캐릭터(Demand Character) 개념과 베일런스(Valence) 개념 그리고 생태심리학과 인지심리학에서 사용되는 어포던스 개념을 심층적으로 고찰하였다. 연구를 통해 인간의 지각이 개별 자극의 조합이 아니라 형태 집단을 인식하는 방식으로 이루어진다는 것을 전제로 하는 게슈탈트 심리학과 생태심리학의 학문적 접근방식에 있어서의 근본적인 공통점들을 발견할 수 있었다. 이러한 맥락을 바탕으로 최종적으로 디맨드 캐릭터의 관찰자 필요에 의한 가변성, 네거티브 개념까지 존재하는 베일런스, 근본적으로 환경에 내재하는 깁슨의 어포던스, 관찰자의 인지 능력에 종속적인 노먼의 어포던스 개념들을 비교분석하였다. 본 연구를 통해 게슈탈트 심리학과 어포던스 개념 간의 연관성을 살펴보고 둘 사이를 관통하는 공통적인 맥락을 조명해 보았다. 이를 바탕으로 향후 디자인 분야에서 두 개념에 대한 활용과 논의가 통합적인 관점에서 보다 구체화 될 수 있기를 기대한다. Gestalt and affordance are psychology contents that are representatively encountered in the design field, and both started from psychological research related to visual perception. However so far, the connection between the two concepts has not been particularly noted and they have been studied individually. This study started from the fact that Gibson, who coined the affordance term, refers to the concept of Gestalt psychologists as the starting point of affordance. Through the research, fundamental commonalities in the academic approach of Gestalt psychology and ecological psychology could be found. Also, the variability due to the need of the observer of the demand character, the veilance that even has a negative direction, Gibson's affordance that is fundamentally inherent in the environment, and Norman's affordance that are dependent on the observer's cognitive ability were compared and analyzed. Based on this study, it is expected that the use and discussion of gestalt and affordance in design field will be more concrete in an integrated perspective.

Design Method for Negative Group Delay Circuits Based on Relations among Signal Attenuation, Group Delay, and Bandwidth

Sehun Na,Youn-Kwon Jung,Bomson Lee 한국전자파학회JEES 2019 Journal of Electromagnetic Engineering and Science Vol.19 No.1

Typical negative group delay circuits (NGDC) are analyzed in terms of signal attenuation, group delay, and bandwidth using S-parameters. By inverting these formulations, we derive and present the design equations (for NGD circuit elements) for a desired specification of the two among the three parameters. The proposed design method is validated through simulation examples for narrow- and wide-band pulse inputs in the time and frequency domains. Moreover, an NGDC composed of lumped elements is fabricated at 1 GHz for measurement. As a function of frequency, the circuit-/EM-simulated and measured group delays are in good agreement. The provided simple NGDC design equations may be useful for many applications that require compensations of some signal delays.

An Empirical Study on the Trust-Building Strategy of Internet Automobile Insurance

Sehun Lim,Sukho Lee,Young Tae Park 한국데이타베이스학회 2008 Journal of information technology applications & m Vol.15 No.3

Trust is emphasized as one of the most important factors in various e-commerce related studies. It is no exaggeration to say that in the area of e-commerce, trust-building with customers determines a company’s success or failure. That is why most e-commerce based companies spare no time and effort in building trust with customers. Without exception, trust is one of the most critical factors influencing a customer’s decision making process of whether to purchase Internet automobile insurance. This study attempts to provide useful guidelines for the sales-enhancing strategies of Internet automobile insurers, by delving into research questions concerning 1) gender differences in Internet automobile insurance customers’ recognition of trust, and 2) gender differences in the effective trust factors influencing one’s intention to purchase of Internet automobile insurance. The study finds that while the shape of trust-recognition toward three types of trust factors is very similar for both gender groups, the intensity of trust for each gender group in overall is pretty different. The results indicate that there exist gender differences in the trust factors influencing one’s intent to purchase Internet automobile insurance. The results of this study will provide useful guidelines for Internet automobile insurers in establishing effective and differentiated marketing strategies.

Effect of Etching Temperature on Adhesion and Surface Morphology of Acrylonitrile-Butadiene-Styrene (ABS) Based Material for Plating

Sehun Han,Injoon Son,Jaesik Seo,Woochul Jung,Sungho Yoon 한국표면공학회 2017 한국표면공학회 학술발표회 초록집 Vol.2017 No.11

Diagnostic accuracy of manual office blood pressure measurement in ambulatory hypertensive patients in Korea

Sehun Kim,Jin Joo Park,Seung-Ah Lee,Youngjin Cho,Yeonyee E. Yoon,Il-Young Oh,Chang-Hwan Yoon,Jung-Won Suh,Young-Seok Cho,Doo Ryeon Chung,Goo-Yeong Cho,In Ho Chae,Hae-Young Lee,Jinho Shin,Sungha Park,D 대한내과학회 2018 The Korean Journal of Internal Medicine Vol.33 No.1

Background/Aims: Currently, office blood pressure (OBP) is the most widely used method of measuring blood pressure (BP) in daily clinical practice. However, data on the diagnostic accuracy of OBP in reference to ambulatory blood pressure (ABP) are scarce in Korea. Methods: In retrospective and prospective cohorts, manual OBP and ABP measurements were compared among ambulatory hypertensive patients. Hypertension was defined as systolic OBP ≥ 140 mmHg and/or diastolic OBP ≥ 90 mmHg, and systolic ABP ≥ 130 mmHg and/or diastolic ABP ≥ 80 mmHg. Results: In the retrospective cohort (n = 903), the mean OBP1 (before ABP measurement) was higher than ABP in both systolic (138 ± 17 mmHg vs. 123 ± 13 mmHg, p < 0.001) and diastolic (84 ± 12 mmHg vs. 78 ± 11 mmHg, p < 0.001) measurements. Interestingly, there was only a weak correlation between OBP and ABP (r2 = 0.038, p < 0.001). The overall discordance rate of OBP compared to ABP, which is the reference method for measuring BP, was 43.9%. The prospective cohort (n = 57) showed similar results. In a subgroup analysis, male patients had higher false negative results (masked or under-treated hypertension) than did female patients (26.1% vs. 17.8%, p = 0.003), whereas female patients had a higher false positive rate (white-coat or over-treated hypertension) than did male patients (28.7% vs. 15.2%, p < 0.001). Conclusions: The diagnostic accuracy of manual OBP is low in reference to ABP. Men and women have different patterns of discordance. These findings indicate that management of hypertensive patients with manual OBP measurements may be suboptimal and encourages the use of ABP in ambulatory hypertensive patients.

Services Innovation Using Web Technology

Sehun Lim(임세헌),Daekil Kim(김대길),Jaehoon Whang(황재훈) 한국산업정보학회 2011 한국산업정보학회논문지 Vol.16 No.5

오늘날 웹사이트는 기업의 경영목표를 달성하기 위한 전략적 수단으로 활용되고 있다. 특히, 최근 다양한 계층의 소비자들에게 관심을 얻고 있는 패밀리 레스토랑에 있어서도 웹사이트의 운영은 소비자에게 만족감을 제공해 주기 위한 서비스로 이용되고 있다. 최근 패밀리 레스토랑을 운영하는 기업들은 전략적 차원의 웹사이트 운영을 시도하고 있고, 이를 통해 패밀리 레스토랑의 홍보 및 마케팅을 수행하고 있다. 이러한 노력은 패밀리 레스토랑의 경영성과 개선에 영향을 미친다. 본 연구에서는 성별에 따라 소비자들의 패밀리 레스토랑 웹사이트의 이용에 대한 분석을 하였다. 연구모델은 기술수용모델을 확장해 성별에 따라 패밀리 레스토랑 웹사이트의 이용용이성과 유용성이 이용의도에 미치는 영향과 실제이용과 추천에 미치는 영향관계를 분석하였다. 본 연구결과는 패밀리 레스토랑 운영 기업들이 소비자들을 대상으로 마케팅 전략을 수립하는데 유용한 시사점을 제시해 줄 것으로 기대한다. Today, a web site is used as a strategic method to fulfill a company’s objectives. In particular, a web site provides a service for customers to find satisfaction in visiting family restaurants, and it recently has helped to attract the interest of a variety of customers. Currently, companies that manage family restaurants operate their Web sites as strategic tools and use them to perform public relations and marketing of their restaurants. This effort influences management and helps to improve the business and profitability of family restaurants. The research model of this study is an expansion of the Technology Acceptance Model (TAM) and examines whether ease of use and usefulness of family restaurant web sites influence the relationship of intention to use, actual use, and recommendation to use by gender. The results of this research would suggest that web sites are useful in establishing a marketing strategy for companies that operate family restaurants.

Apparent treatment-resistant hypertension among ambulatory hypertensive patients: a cross-sectional study from 13 general hospitals

( Sehun Kim ),( Jin Joo Park ),( Mi-seung Shin ),( Choong Hwan Kwak ),( Bong-ryeol Lee ),( Sung-ji Park ),( Hae-young Lee ),( Sang-hyun Kim ),( Seok-min Kang ),( Byung-su Yoo ),( Joong-wha Chung ),( S 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.4

Background/Aims: To examine the prevalence and clinical characteristics of apparent treatment-resistant hypertension among ambulatory hypertensive patients. Methods: We enrolled adult ambulatory hypertensive patients at 13 well-qualified general hospitals in Korea from January to June 2012. Apparent resistant hypertension was defined as an elevated blood pressure > 140/90 mmHg with the use of three antihypertensive agents, including diuretics, or ≥ 4 antihypertensives, regardless of the blood pressure. Controlled hypertension was defined as a blood pressure within the target using three antihypertensives, including diuretics. Results: Among 16,915 hypertensive patients, 1,172 (6.9%) had controlled hypertension, and 1,514 (8.9%) had apparent treatment-resistant hypertension. Patients with apparent treatment-resistant hypertension had an earlier onset of hypertension (56.8 years vs. 58.8 years, p = 0.007) and higher body mass index (26.3 kg/㎡ vs. 24.9 kg/㎡, p < 0.001) than those with controlled hypertension. Drug compliance did not differ between groups. In the multivariable analysis, earlier onset of hypertension (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.97 to 0.99; p < 0.001) and the presence of comorbidities (OR, 2.06; 95% CI, 1.27 to 3.35; p < 0.001), such as diabetes mellitus, ischemic heart disease, heart failure, and chronic kidney disease, were independent predictors. Among the patients with apparent treatment-resistant hypertension, only 5.2% were receiving ≥ 2 antihypertensives at maximally tolerated doses. Conclusions: Apparent treatment-resistant hypertension prevalence is 8.9% among ambulatory hypertensive patients in Korea. An earlier onset of hypertension and the presence of comorbidities are independent predictors. Optimization of medical treatment may reduce the rate of apparent treatment-resistant hypertension.

Clinical significance of high on-treatment platelet reactivity in patients with prolonged clopidogrel therapy

( Sehun Kim ),( Donghoon Han ),( Jae Hyuk Choi ),( Eun-joo Park ),( Dong Geum Shin ),( Min-kyung Kang ),( Seonghoon Choi ),( Namho Lee ),( Jung Rae Cho ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.0

Background/Aims: Prolonged dual antiplatelet therapy (DAPT) with aspirin and clopidogrel beyond 1 year has been shown to reduce ischemic events at the expense of increased bleeding. However, limited data are available on the clinical significance of platelet reactivity (PR) at 1 year. Methods: We retrospectively identified 331 patients who underwent percutaneous coronary intervention (PCI) and assessed the on-clopidogrel PR using VerifyNow P2Y12 assay at 1 year in a single center. Two hundred eleven patients were on DAPT for > 1 year. The relationship between high on-treatment platelet reactivity (HPR) at 1 year and clinical outcomes beyond 1 year, as well as the longitudinal change in PR was analyzed. Results: At 1 year, 135 (64%) patients showed HPR and 76 (36%) did not. There was a significant increase in ischemic endpoint events, including cardiovascular death, non-fatal myocardial infarction, and stroke/transient ischemic attack in patients with compared to without HPR at 1 year (hazard ratio [HR], 2.68; 95% confidence interval [CI], 1.06 to 6.77; p = 0.036). However, the incidence of any Bleeding Academic Research Consortium bleeding was significantly lower in the HPR group (HR, 0.11; 95% CI, 0.02 to 0.65; p = 0.015). In the longitudinal analysis, PR significantly decreased from post-load to 1 year after index PCI in the non-HPR group. Conversely, the HPR group showed high PR from baseline through 1 year. Conclusions: HPR at 1 year may be a useful surrogate for predicting ischemic and bleeding events in patients on prolonged DAPT. Patients with and without HPR at 1 year showed different patterns of longitudinal change in PR.

The Effect of Providing Audiovisual Surgical Information on Decisional Conflict in Patients Undergoing Plate Fixation for Distal Radius Fractures

Sehun Kim,Hyun Sik Gong 대한정형외과학회 2021 Clinics in Orthopedic Surgery Vol.13 No.1

Background: Patients experiencing acute trauma have limited time for their involvement in shared decision making, which may lead to decisional conflict. The purpose of this study was to evaluate whether providing audiovisual surgical information can reduce decisional conflict when deciding between surgical and nonsurgical treatment in patients with distal radius fractures (DRFs) and to evaluate factors that may affect decisional conflict. Methods: We prospectively enrolled 50 consecutive patients who presented with acute DRFs and chose to undergo surgery, for which volar plate fixation was recommended. We randomized these patients into 2 groups. The test group was given a video clip of audiovisual surgical information in addition to regular information while the control group was only given regular information. The video clip consisted of the purpose, procedure, and effect of the surgery, precautions and complications after the operation, and other treatment options that could be performed if operation was not performed. At 2 weeks after the surgery, we evaluated patients’ decisional conflict using a decisional conflict scale (DCS). In addition, we evaluated factors that might affect decisional conflict, such as age, dominant hand, comorbidities, history of previous operations, perceived disability, and provision of the video clip. Results: The test group showed significantly lower DCS scores than the control group (19.6 vs. 32.1, p = 0.001). In multivariate analysis, younger age and provision of the video clip were associated with lower DCS scores. Conclusions: This study has demonstrated that providing information through audiovisual media such as video clips could reduce decisional conflict in patients who chose to undergo plate fixation for DRFs. This study also suggests that older patients may need more careful doctor-patient communication as they have more decisional conflict than younger patients.