• Convergence Security Journal
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• v.18 no.2
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• pp.49-58
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• 2018

As the demand for Internet of Things(IoT) increases, the need for the security of IoT devices is increasing steadily. It is difficult to apply the conventional security theory to IoT devices because IoT devices are subject to be constrained by some factors such as hardware, processor, and energy. Nowadays we have several security guidelines and related documents on IoT device. Most of them, however, do not consider the characteristics of specific IoT devices. Since they describes the security issues comprehensively, it is not easy to explain the specific security level reflecting each characteristics of IoT devices. In addition, most existing guidelines and related documents are described in view of developers and service proposers, and thus ordinary users are not able to assess whether a specific IoT device can protect their information securely or not. We propose an security evaluation model, based on the existing guidelines and related documents, for more specific IoT devices and prove that this approach is more convenient to ordinary users by creating checklists for the smart watch.

• Journal of IKEEE
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• v.26 no.4
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• pp.671-680
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• 2022

In this paper, A 200kW traction motor driver that covers most of the traction motor specification of commercial electric vehicles (EV) is developed. In order to achieve high efficiency and high power density, a next-generation power semiconductors (Silicon carbide, SiC) are applied instead of power semiconductor(IGBT), which is Si based. Through hardware analysis for optimal use of SiC, expected efficiency and heat dissipation characteristics are obtained. A vector control algorithm for an IPMSM (Interior permanent magnet synchronous motor), which is mostly used in EV(Electric vehicle) traction motor, is implemented using DSP (Digital signal processor). In this paper, a prototype traction motor driver based SiC for EV is designed and manufactured, and its performance is verified through experiments.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.788-797
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• 2023

In this paper, we introduced a test environment to test a vision-aided navigation system, as an alternative navigation system when global positioning system (GPS) is unavailable, for vertical take-off and landing (VTOL) unmanned aerial system. It is efficient to use a virtual environment to test and evaluate the vision-aided navigation system under development, but currently no suitable equipment has been developed in Korea. Thus, the proposed test environment is developed to evaluate the performance of the navigation system by generating input signal modeling and simulating operation environment of the system, and by monitoring output signal. This paper comprehensively describes research procedure from derivation of requirements specifications to hardware/software design according to the requirements, and production of the test environment. This test environment was used for evaluating the vision-aided navigation algorithm which we are developing, and conducting simulation based pre-flight tests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.166-172
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• 2016

This paper deals with the seismic qualification of the reflective metal insulation for thermal shielding that is installed on the outer surfaces of the main equipment of the primary coolant system of a nuclear power plant. A small-scale model of the reactor pressure vessel, which has equivalent dynamic characteristics, was designed to be tested in domestic seismic testing facilities in the future. In this study, seismic analysis of the small-scale model installed with metal insulation was performed using equivalent static analysis and response spectrum analysis. The required Response Spectrum for main equipment of the primary coolant system of APR-1400 plant were considered to establish the enveloping response spectrum, which was applied to the seismic analysis model. The results from two seismic analysis methods were compared to show the structural adequacy of the metal insulator design against a safe shutdown earthquake. This study will form the basis for the seismic testing to support the seismic qualification of the reflective metal insulator.

• Korean Journal of Construction Engineering and Management
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• v.13 no.5
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• pp.84-93
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• 2012

Most of the studies on reduction of buildings' environmental burden in the construction industry have been focused on carbon dioxide emission, although there are various kinds of environmental issues such as global warming, acidification, and etc. which are considered by many researchers. Therefore, this study defined and suggested six impact categories and the principles to assess each impact for the assessment of comprehensive environmental impacts of buildings. The six impact categories are abiotic depletion, global warming, ozone layer depletion, acidification, eutrophication, and photochemical oxidation. A case study has been conducted through comparative analysis of two structural design alternatives to confirm the necessity of assessing the six impact categories. That is, the results of global warming potential and the six impacts proposed in this study were compared. By comparing the results of only global warming potential, the second design alternative using 24MPa concrete was chosen as a better alternative, while the first design alternative using 21MPa concrete was resulted as a better alternative when six impact categories were considered. The results mean that the assessment of various environmental impacts is an appropriate and reasonable approach and the comprehensive assessment offers more reliable results of environmental impacts in the building construction.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.67-76
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• 2009

Recently, the active interaction control (AIC) system was proposed as a semi-active control system. The AIC system consists of a primary structure and an auxiliary structure. The objective of the AIC system is to control the response of the primary structure through engagement and disengagement between the primary and auxiliary structures. Previous switching control algorithms have been shown to be effective in reducing the response of the primary structure. However, they have the main drawback of requiring an excessive engagement-disengagement frequency and high interaction force. In this paper, the regions in which the switching is activated and the regions in which the switching is deactivated are described separately, to effectively determine the engagement or the disengagement. The general relationship between the switching regions and the deactivated switching regions selected according to the engagement-disengagement conditions is described within the newly-developed comprehensive switching framework. The proposed engagement-disengagement conditions are designed within a comprehensive switching framework, to reduce engagement-disengagement frequency and interaction force. Furthermore, the effect of a control sampling period on the AIC system is explained in terms of the engagement-disengagement frequency. The effectiveness of the proposed algorithms and the effect of the control sampling period are considered for a single degree of freedom model under free vibration. It is observed that increasing the duration of stay by using a large control sampling period prevents the AIC system from activating the possible chance of switching. The proposed algorithms are shown to be effective, both in restricting ineffective switching and in reducing interaction force.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.674-681
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• 2021

Cyber attacks targeting critical infrastructure are on the rise. Critical infrastructure is defined as core infrastructures within a country with a high degree of interdependence between the different structures; therefore, it is difficult to sufficiently protect it using outdated cybersecurity techniques. In particular, the distinction between the physical and logical risks of critical infrastructure is becoming ambiguous; therefore, risk management from a comprehensive perspective must be implemented. Accordingly, as a means of further actively protecting critical infrastructure, major countries have begun to apply their security and cybersecurity systems by design, as a more expanded concept is now being considered. This proactive security approach (CSbD, Cybersecurity by Design) includes not only securing the stability of software (SW) safety design and management, but also physical politics and device (HW) safety, precautionary and blocking measures, and overall resilience. It involves a comprehensive security system. Therefore, this study compares and analyzes security by design measures towards critical infrastructure that are leading the way in the US, Europe, and Singapore. It reflects the results of an analysis of optimal cybersecurity solutions for critical infrastructure. I would like to present a plan for applying by Design.

• Therapeutic Science for Rehabilitation
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• v.11 no.1
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• pp.21-33
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• 2022

Purpose : The purpose of this study was to establish scientific evidence though a systematic review, of the existing interventional methods and their respective effects, for swallowing disorders among dementia patients. The interventional methods were based on patient characteristics. Methods : An electronic literature search was performed using five electronic databases from 2010 to 2020. The keywords were 'Dementia', 'Alzheimer disease', 'Deglutition disorder', 'Swallowing disorder', 'Dysphagia'. Five articles met the inclusion criteria. Results : One study with moderate-to-severe and four studies with severe dementia patients were included. The interventions consisted of one remedial intervention, three compensatory interventions, and one comprehensive intervention. Compensatory intervention, including behavioral and psychological management, were used in moderate-to-severe patients. For the severe patients, remedial, compensatory, and comprehensive intervention were used to address the feeding tube problem. The interventions used in each study had a positive effect on the outcome variables associated with swallowing ability. Conclusion : The purpose of the intervention and the intervention factors changed depending on the patient's dementia stage. The intervention was effective when considering the progressive stage of the patient. These results may serve as a guide in designing effective interventions for swallowing disorders in dementia patients.

• Therapeutic Science for Rehabilitation
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• v.12 no.4
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• pp.135-151
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• 2023

Objective : This study was conducted to confirm the effect of the oral motor facilitation technique (OMFT) on oral motor function in stroke patients. Methods : This study was conducted on 72 stroke patients with dysphagia were included. Thirty-six patients were randomly assigned to the experimental and control groups were randomly classified into 36 patients each using a random table, and a two-group pre-post test was designed. The experimental group underwent OMFT, and the control group underwent traditional dysphagia therapy for 30 min, once a day, 5 times a week for 4 weeks, for a total of 20 sessions. The Comprehensive Orofacial Function Scale (COFFS) was used to evaluate oral motor function. Repeated-measures analysis of variance (ANOVA) was performed to confirm the effect of the period, and an independent t-test was performed to analyze the difference in change between the two groups. Results : Total COFFS scores improved in both groups. The experimental group showed significant changes in mandibular and lip movements, cheek blows, and tongue movements. In addition, there were significant differences depending on the intervention period in terms of masticatory distribution, food spillage, swallowing of solid and liquid foods, and voice changes. There were significant differences in the mandibular opening and closing categories between the two groups. Conclusion : OMFT is effective in improving oral motor function in stroke patients with dysphagia and can be used as basic evidence in clinical practice.

• Korean Journal of Construction Engineering and Management
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• v.12 no.5
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• pp.12-22
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• 2011

Design value engineering (VE) has been performed in many construction projects according to the changes in the construction for most of the VB function analysis that performed, are problems that focus on function analysis and generating ideas based on individual experience of VE team member than generating ideas and value improvement of systematic function analysis. This may be due to the quotation of previously performed function analysis data, general function analysis, and abstract function definitions that do not cite the concrete characteristics of each facility. Therefore, in this study, the proposed cases from the existing design VE workshops, the current conditions of the connection between functions and ideas and of the idea categorization by building part were studied to determine why functions and ideas are not connected, and to propose pertinent improvement directions. on a performance-based function categorization system by building part that can provide the logical connection between functions and ideas in the function definition/categorization and function arrangement phases in the function analysis phase, the most important phase in VE activities, was developed by reflecting the required performance and functions for each part of the facility.