Optimal Rhythm Control Strategy in Patients With Atrial Fibrillation

Daehoon Kim,Pil-Sung Yang,Boyoung Joung 대한심장학회 2022 Korean Circulation Journal Vol.52 No.7

For almost 20 years, data regarding the effect of rhythm control therapy for atrial fibrillation (AF) on cardiovascular prognosis in comparison with rate control therapy has not been conclusive. The safety of rhythm control and anticoagulation therapy has generally improved. Recently, it was revealed that a rhythm-control strategy reduced the risk of adverse cardiovascular events than usual rate control in patients with recent AF (diagnosed within 1 year). Within 1 year after the AF diagnosis, early initiation of rhythm control led to more favorable cardiovascular outcomes than rate control. Early rhythm control reduced the risks of stroke and heart failure-related admission than rate control. Moreover, rhythm control was associated with lower dementia risk than rate control. Finally, early rhythm control treatment was also effective in patients with asymptomatic AF but less effective in older adults. Therefore, in patients with AF, rhythm control should be considered at earlier stages, regardless of symptom.

Virtual Snooping Coherence for Multi-Core Virtualized Systems

Daehoon Kim,Chang Hyun Park,Hwanju Kim,Jaehyuk Huh IEEE 2016 IEEE transactions on parallel and distributed syst Vol.27 No.7

<P>Proliferation of virtualized systems opens a new opportunity to improve the scalability of multi-core architectures. Among the scalability bottlenecks in multi-cores, cache coherence has been one of the most critical problems. Although snoop-based protocols have been dominating commercial multi-core designs, it has been difficult to scale them for more cores, as snooping protocols require high network bandwidth and power consumption for snooping all the caches. In this paper, we propose a novel snoop-based cache coherence protocol, called virtual snooping, for virtualized multi-core architectures. Virtual snooping exploits memory isolation across virtual machines and prevents unnecessary snoop requests from crossing the virtual machine boundaries. Each virtual machine becomes a virtual snoop domain, consisting of a subset of the cores in a system. Although the majority of virtual machine memory is isolated, sharing of cachelines across VMs still occur. To address such data sharing, this paper investigates three factors, data sharing through the hypervisor, virtual machine relocation, and content-based sharing. In this paper, we explore the design space of virtual snooping with experiments on emulated and real virtualized systems including the mechanisms and overheads of the hypervisor. In addition, the paper discusses the scheduling impact on the effectiveness of virtual snooping.</P>

Prevention of Dementia in Patients with Atrial Fibrillation

Daehoon Kim,Pil-Sung Yang,정보영 대한심장학회 2021 Korean Circulation Journal Vol.51 No.4

Atrial fibrillation (AF) is the most common form of arrhythmia in the elderly population and increases stroke risk by a factor of 4- to 5-fold. There is increasing evidence to suggest that incident AF may contribute to the development of dementia, independent of overt stroke. In particular, relatively younger patients with AF are more prone to dementia development than older patients with AF. Evidence is accumulating regarding the possible treatment strategies for preventing dementia in patients with AF. Oral anticoagulation may be effective for reducing the risk of dementia, even in patients with low stroke risks. Among oral anticoagulants, the use of non-vitamin K antagonists have been associated with a considerably decreased risk of dementia than warfarin. Moreover, successful catheter ablation for AF has also been associated with decreased dementia risk compared to medical therapy, suggesting that restoration of sinus rhythm, and not the ablation procedure itself, as the important mechanism in the prevention of AF-associated dementia. Among midlife patients with AF, there appeared to be a U-shaped association of blood pressure (BP) and a linear association of hypertension with dementia risk. A BP of 120 to 129/80 to 84 mmHg has been identified as the optimal range. Finally, integrated management of AF was associated with a reduced risk of dementia in AF patients.

S-276 Immediate and late outcomes of percutaneous transluminal angioplasty in Buerger``s disease

( Daehoon Kim ),( Young-guk Ko ),( Chul-min Ahn ),( Dong-ho Shin ),( Jung-sun Kim ),( Byeong-keuk Kim ),( Donghoon Choi ),( Myeong-ki Hong ),( Yangsoo Jang ) 대한내과학회 2016 대한내과학회 추계학술대회 Vol.2016 No.1

Objectives: The aim of this study was to appraise clinical outcomes after percutaneous transluminal angioplasty (PTA) for Buerger's disease patients with lower extremity artery disease. Methods: Between January 2006 and May 2015, 43 consecutive Buerger's disease patients with 48 target limbs were treated by PTA. The primary endpoint was clinically driven target lesion revascularization (TLR) at 24 months. Secondary endpoints included limb salvage rate, survival free from unexpected amputation, and changes in Rutherford class, ankle-brachial index (ABI). Results: Technical success using PTA was achieved in 35 (72.9%) of 48 limbs. The mean treated lesion length was 201±14 mm, including 39.6% multi-level lesions, 70.8% below-the-knee lesions, and 77.1% total occlusions. Clinical success rate was 70.8% with a significant improvement in Rutherford classes (p<0.001) and significantly increased ABIs, from 0.62±0.05 to 0.85±0.04 (p<0.001). At 24 months, the rate of clinically driven TLR was 23.1%, and limb salvage rate was 87.2% with 5 major amputations. The rate of freedom free from unexpected amputations was 91.7% with 3 unexpected amputations. Continuing smoking after PTA was the only independent predictor of TLR (HR: 5.10; 95% CI: 1.08 to 24.04, p=0.039).?Conclusions: PTA was feasible and effective for the revascularization in Buerger's disease patients. Technical success was achieved in the majority of the patients and the freedom free from clinically driven TLR and amputation at 2-year follow-up were favorable.

Thermodynamic Modeling on Composite Insulation for Liquid Hydrogen Storage Tank

Daehoon Kang,Sungho Yun,Bo-Kyong Kim,Gil Dong Kim 한국신재생에너지학회 2021 AFORE Vol.2021 No.10

The effects of monetary policy on consumption, housing wealth and house prices: An Australian perspective

( Daehoon Nahm ),( Joseph Macri ) 한양대학교 경제연구소 2016 JOURNAL OF ECONOMIC RESEARCH Vol.21 No.2

We employ a specially-structured VAR model to firstly examine the total effects of Australia``s monetary policy changes on private sector variables, specifically, household consumption, housing wealth, and house prices, through impulse responses. We then utilise the special structure of the model to decompose the total effect of monetary policy changes on consumption into the direct effect from changes in the cost of credit, the indirect wealth effect from changes in house prices and housing wealth, and the feedback effect from the reaction of the Reserve Bank of Australia to changes in consumption, house prices and housing wealth. Our results suggest that a deliberate monetary policy shock has a significant effect on house prices, but only a marginal effect on consumption. We also introduce a novel approach to identify the elements of the impulse response function in decomposing the total consumption effect into direct, indirect and feedback effects.

4D Printing of Bio-inspired Devices: Microneedle and Artificial Chromatophore

Daehoon Han(한대훈) 한국고분자학회 2022 한국고분자학회 학술대회 연구논문 초록집 Vol.47 No.2

U-shaped Reconfigurable Field-effect Transistor

Daehoon Wee,Hui Tae Kwon,Won Joo Lee,Hyun-Seok Choi,Yu Jeong Park,Boram Kim,Yoon Kim 대한전자공학회 2019 Journal of semiconductor technology and science Vol.19 No.1

We propose a novel reconfigurable fieldeffect transistor (RFET) featuring two verticallystacked gates and a U-shaped nanowire channel. Conventional RFETs have a relatively large unit cell size due to their configuration with multiple gates. However, the proposed device can solve this inherent disadvantage of RFET. In addition, it can have a long enough channel without additional area, so that excellent characteristics can be obtained without the short channel effects. The characteristics of the proposed device were examined by 3-D technology computer-aided design (TCAD) device simulation. The effect of some device parameters on the device performance were investigated. Also, the fabrication method is proposed.

Liquid Hydrogen Powered Locomotive

Daehoon Kang 한국신재생에너지학회 2022 AFORE Vol.2022 No.9

Teachers' Professional Role Conflicts In Korean Public Middle Schools

Daehoon Jho(조대훈) 성신여자대학교 교육문제연구소 2004 교육연구 Vol.38 No.-

본 논문은 서울에 위치한 공립 남녀 공학 중학교에 근무하는 사회과 교사들의 교직 업무에 관한 문화기술적 사례연구(ethnographic case study)이다. 연구자는 한국 중학교 제도 문화 안에서 사회과 교사들의 일상 업무를 탐색하면서, 한국 중학교 교사들의 업무가 지니는 세 가지의 다면적 역할(multifaceted nature), 즉 담임교사-하위 행정관료-교과전문가로서의 역할을 기술하고, 이러한 독특한 교사의 일 구조가 교과교육에 시사하는 바를 검토하였다. 연구자는 ‘한국 중학교에서의 교사의 일’이 어떻게 구성되는지를 검토하는 과정에서 크게 다음의 세 가지 이론적 가정들을 출발점으로 삼았다. 1) 사회과 교사들의 업무는 주어진 학교 제도 문화 안에서 사회적-문화적으로 구성된다. 2) 학교의 행정구조는 교사들의 일을 분석하는데 있어 중요한 맥락적 변인(contextual factors)으로 작용한다. 3) 교사들은 이미 결정된 지식과 기능의 중립적 전달자가 아니라, 계속적으로 교육과정적-교수적 의사 결정을 내리고 적절한 행동을 취하는 “교육적 조율자(educational gatekeeper)"로서 역할을 한다. 교실 수업 관찰, 심층 면접, 학교 문서 등의 질적 자료의 분석을 통해 연구자는 다음과 같은 잠정적 결론들을 얻어냈다. 첫째, 교과 전문가, 하위 행정 관료, 담임교사로서의 다중적인 교사의 역할은 사회과 교사가 담당하는 일상 업무의 심화성(intensification)을 발생시키고 있었다. 사회과 교사들은 일상적인 교수 활동의 준비보다, 그것과 직접적 관련이 없는 업무들을 수행하는데 상대적으로 더 많은 시간과 정력을 소비하고 있었다. 둘째, 특히 행정적 영역과 교수적 영역 간에서 발생하는 구조적 괴리(structural decoupling)는 교사 개인 그리고 학교 차원에서 모두 나타나고 있었다. 이러한 행정-교수 영역의 구조적 괴리는 결과적으로 행정적 효율성을 위해 교과교육적 목적을 간과하는 학교의 문화적 분위기를 반영하였다. 셋째, 이상의 결과들은 교과전문가로서의 사회 교사의 역할-지위에 부정적인 영향을 미쳤고, 교과교육의 강화를 추구하는 교육당국의 정책과는 모순되는 상황을 야기하고 있었다. 달빛 중학교의 사례는 “교사는 가르치는 자이며, 학교는 그러한 교사의 교수 활동을 지원한다”는 대중의 상식은 상당히 단순화된 것일 수 있다는 점을 강력하게 시사하고 있다. This ethnographic case study situates the meaning of social studies teacher's work in the institutional context of Korean public middle schools. By describing the multifaceted nature of social studies teachers' work in the given context, this study analyzes their professional role conflicts and implications for social studies instruction. Based on the data drawn from in-depth interviews, classroom observations materials, and school materials, I identified the three distinctive roles that most teachers in Korean public middle schools assume on a daily basis: those of homeroom manager, administrative bureaucrat, and subject matter educator. In conclusion, I maintain in this paper that social studies teachers' work, especially the work of those in majority who were homeroom teachers, was intense in nature. More importantly, I argue that, within the institutional culture of the school, the social studies teachers' administrative practices were almost completely separated from their daily instructional practices. This, what I call, structural decoupling between the administrative and the instructional domains is exacerbating the social studies teachers' role-conflict between their administrative and instructional roles, ultimately having a detrimental effect on subject matter education.