• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.575-583
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• 2004

In this paper, we extend the multiple time scale control framework to the window-based congestion control, in particular, such as the TCP. This is performed by interfacing the TCP with a large time scale control module which adjusts the aggressiveness of the bandwidth consumption behavior exhibited by the TCP as a function of large time scale Self-Similar network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by the RTT. How to effectively utilize such an information-due to its probabilistic nature, dispersion over the multiple time scales, and affection on the top of the existing window-based congestion controls-is a non-trivial problem. The evaluation performance of the multiple time scale TCP is facilitated by a simulation of the bench-mark environment which is based on the physical modeling of a self-similar traffic. We explicate our methodology for discerning and evaluating the impact of changes in transport protocols in the protocol stack under the self-similar traffic conditions. We discuss issues arising in the comparative performance evaluation under heavy-tailed workloads.

• Journal of KIISE:Software and Applications
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• v.33 no.3
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• pp.316-334
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• 2006

In the traditional computing paradigm, developers design software to run in a fixed and well-defined environment. The real environment, however, is too complicated to analyze all situations perfectly. Consequently, traditional software, which is implemented only for what is wanted as input, often fails badly in real environment. As a new approach, self-adaptive software can avoid runtime failures adapting to unpredictable situations. Self-adaptive software must firstly evaluate the contextual situation to determine the need for adaptation. Existing researches do not support the abstraction mechanism for identifying contextual problem. Consequently, they can have troubles with identifying the contextual problem as the execution environment is getting complex. In addition, they cannot support the expandability for contextual problems, which software can evaluate. This paper suggests the goal-based evaluation method of contextual situation for coping with the limitations of existing researches.

• Composites Research
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• v.36 no.3
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• pp.141-153
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• 2023

This review paper presents an introduction of contact mechanics and rubber friction theory for sliding friction of elastomer composites in contact with rough surfaces. Particularly, Klüppel & Heinrich theory considers the self-affine (or fractal) characteristic for rough surfaces to predict adhesion and hysteresis frictions of elastomers based on the contact mechanics of Greenwood & Williamson. Due to dynamic excitation process of elastomer composites while sliding in contact with multiscale surface roughness (or asperity), viscoelastic properties in a wide frequency range becomes major contributor to friction behaviors. A brief description and examples are provided to construct a viscoelastic master curve considering nonlinear viscoelasticity of elastomer composites. Finally, application of rubber friction theory to tire tread compounds in traction with road surfaces is discussed with several experimental and theoretical results.

• Korean Journal of Medical Ethics
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• v.21 no.4
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• pp.301-315
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• 2018

Women have been entrusted with responsibility for pregnancy, childbirth, and nurturing by means of socially imposed 'maternity' along with their physical characteristics. Abortion too involves the bodies of women, and women are the ones most affected by it. However, women do not yet have the right of self-determination over their bodies. In the "pro-choice versus pro-life" abortion debate in South Korea, women's self-determination is often treated with less significance than the alleged "respect for life." Moreover, as Korea's declining fertility rate has become a serious social problem, women's perspectives on the issue of abortion have been sidelined. Yet even in this context, there is a double standard between the treatment of disabled and able-bodied women. The purpose of this study is to examine the issue of self-determination, especially for women with disabilities, from the perspective of a capability approach. The following three recommendations are proposed: (a) that the various contextual variables of disabled women are included in the concept of self-determination; (b) that a solid relationship between individuals and communities is established in order to ensure the realization of the right of self-determination for disabled women; and (c) that the discourse of "reproduction rights" (i.e. comprehensive rights of women with disabilities) be expanded.

• Investigative Magnetic Resonance Imaging
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• v.12 no.1
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• pp.40-48
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• 2008

Purpose : We sought to determine the early change of ventricular geometry and function after concomitant surgeries of modified Dor procedure and mitral valve annuloplasty by using magnetic resonance imaging. Materials and Methods : We enrolled 21 patients with dilated heart failure who underwent modified Dor procedure (n=8), mitral valve annuloplasty (n=6), or both surgeries (n=7). Cine MRI was used to assess left ventricular dimensions and function before and after surgery. We measured the left ventricular end-diastolic and end-systolic volumes and the dimensions of the left ventricular long-axis and short-axis. Left ventricular stroke volume, ejection fraction, and sphericity index were calculated from these measurements. These parameters were analyzed and compared between three different surgery groups to explain the combined effect of the concomitant surgeries. Results : MRI was performed within average $12\;{\pm}\;15$ days (range 1-58 days) before and $38\;{\pm}\;50$ days (range 7- 231 days) after the surgery. The patients who underwent concomitant surgeries had more profound enlargement of left ventricle and decreased contractility prior to surgery than those in the patients who underwent single surgical procedure. Left ventricular end-diastolic volume and endsystolic volume significantly decreased in all patients regardless of surgery type after surgery. Ejection fraction significantly increased only in the patients who got modified Dor procedure without mitral valve annuloplasty (25.4% to 40.7%). Sphericity index increased in patients with modified Dor procedure but decreased in patients with mitral valve annuloplasty (0.65 to 0.78 vs. 0.75 to 0.65). In the patients who underwent concomitant surgeries showed no significant change in sphericity index after surgery. Conclusion : The early change of the left ventricular geometry and function after the concomitant surgeries with modified Dor procedure and mitral valve annuloplasty in patients with dilated heart failure includes a marked reduction in left ventricular volume and in stroke volume. The shape of the left ventricle does not change because the effect of sphericity index decrease from mitral valve annuloplasty is counteracted by the effect of sphericity index increase from modified Dor procedure. Improvement of left ventricular ejection fraction is not the early change after the concomitant surgeries.

• Journal of the Korean Society of Radiology
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• v.8 no.5
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• pp.231-240
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• 2014

The purpose of this study were to analyze that the Seoul neuropsychological screening battery (SNSB) for the evaluating cognitive assessment of the Parkinson's disease patients with mild cognitive impairment (PD-MCI) and the changes of the cerebral ventricle volume in the brain magnetic resonance imaging (MRI), and we has been bring forward the guideline to determine the diagnostic criteria for the PD-MCI. To achieve this, we was diagnosed with Parkinson's disease patients (PD-MCI group: 34 patients; Parkinson's disease with normal cognition, PD-NC group: 34 patients) to perform the SNSB test for the attention, language, memory, visuospatial, and frontal/executive functions and the brain MRI. Additionally, to compared the change of the cerebral ventricle volume, we performed the brain MRI for the 32 normal control (NC) group. The volumetric analysis for a specific cerebral ventricle performed by using Freesurfer Ver. 5.1 (Massachusetts general Hospital, Boston MA, USA). As a results, compared to the PD-NC group, the PD-MCI group were statistically significant reduction in the ability to perform the memory and the visuospatial function (p<0.05). The volumetric changes for a specific cerebral ventricle were statistically significant variation in the left and right lateral ventricle, left and right inferior lateral ventricle, and 3rd ventricle. Although, in order to compared the objectification, the normalized percentage applied to the volumetric changes showed to extend the PD-MCI group than the PD-NC group. Specially, the left and right ventricle extension for the PD-MCI patients conspicuously had showed a quantitative linear relationship between the memory and the visuospatial function for the SNSB (r>0.5, p<0.05). Therefore, we were able to judge the diagnostic criteria of the PD-MCI through that can observe the volumetric variation of the specific cerebral ventricle by using Freesurfer in brain MRI, and to analyze the correlation between the SNSB.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.229-236
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• 2019

This study aims to examine the moderating effect of Extended Song Sharing for helping alcoholics to deal with stress. ESS is structure with non-verbal techniques approaches traditional Song Sharing technique. For this study, 64 alcoholics hospitalized were experimental (n=33) and control groups (n=31). The group was asked to participate in 12 ESS programs twice a week, every 45 minutes for six weeks. During this period, all those who belonged to the experimental and control groups were required to continue to participate in treatment programs prescribed by hospitals. Result: ESS interventional effects on subjects were evaluated using a stress response scale. As a result of the experiment, the WCC score of the experimental group increased 7.3% (p=0.000) but there was almost no change in the control group (1.5% increase, p=0.019). Effects of WCC types were higher in the experimental group, followed by 13.67% (p=0.006) in coping with wishful thinking, 9.66% (p=0.000) in the pursuit of social support, 6.35% (p=0.000) in dealing with problems, and 4% (p=0.000) in coping with emotions. ESS activities have been confirmed to improve the way alcoholics cope with stress.

• Journal of Internet of Things and Convergence
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• v.8 no.6
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• pp.115-122
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• 2022

Recently, the importance of CPR training for the layperson has been emphasized to improve the survival rate of out-of-hospital cardiac arrest patients. An accurate and realistic training strategy is required for the CPR training effect for laypersons. In this study, we develop an extended reality (XR) based CPR training system and evaluate its usability. The XR based CPR training system consisted of three applications. First, a 3D heart anatomy image registered to the manikin is transmitted to the smart glasses to guide the chest compression point. The second application provides visual and auditory information about the CPR process through smart glasses. At the same time, the smartwatch sends a vibration notification to guide the compression rate. The 'Add-on-kit' is a device that detects the depth and speed of chest compression via sensors installed on the manikin and sends immediate feedback to the smartphone. One hundred laypersons who participated in this study agreed that the XR based CPR training system has realism and effectiveness. XR based registration technology will contribute to improving the efficiency of CPR training by enhancing realism, immersion, and self-directed learning.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.9
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• pp.797-805
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• 2013

In this paper vibration and stability analysis of laminated composite shells based on the first order shear deformation theory(FSDT) for two different boundary conditions(clamped-clamped, simply supported) are performed. Structural model of cross-ply symmetric laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations(Faraday, Ampere, Ohm, and Lorenz equations)and thermal equations which are involved in constitutive equations. Extended Galerkin method is adopted to obtain the discretized equations of motion. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, laminate thickness-ratio and radius ratio for two boundary conditions are investigated and pertinent conclusions are derived.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.803-810
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• 2013

Since 2004, community childcare centers are legislated and the centers are running as the concept of community-oriented child welfare services. Recently child welfare paradigm are changed from simple "study room" for protection to the future capabilities of the "social welfare". For children who grow in their community, it must request to new construction with ecological system.