• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.205-212
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• 2018

In order to overcome shortcomings of commercial analysis program for solving certain geotechnical problems, finite element method adopting isoparametric quadrilateral element was selected as a tool for analyzing soil behavior and calculating process was programmed. Two examples were considered in order to verify reliability of the developed program. One of the two examples is the case of acting isotropic confining pressure on finite element and the other is the case of acting shear stress on the sides of the finite element. Isoparametric quadrilateral element was considered as the finite element and displacements in the element can be expressed by node displacements and shape functions in the considered element. Calculating process for determining strain which is defined by derivatives using global coordinates was coded using the Jacobian and the natural coordinates. Four point Gauss rule was adopted to convert double integral which defines stiffness of the element into numerical integration. As a result of executing analysis of the finite element under isotropic confining pressure, calculated stress corresponding to four Gauss points and center of the element were equal to the confining pressure. In addition, according to the analyzed results for the element under shear stress, horizontal stresses and vertical stresses were varied with positions in the element and the magnitudes and distribution pattern of the stresses were thought to be rational.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.126-136
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• 2018

The purpose of this study was to develop a severity-adjustment model for predicting mortality in acute stroke patients using machine learning. Using the Korean National Hospital Discharge In-depth Injury Survey from 2006 to 2015, the study population with disease code I60-I63 (KCD 7) were extracted for further analysis. Three tools were used for the severity-adjustment of comorbidity: the Charlson Comorbidity Index (CCI), the Elixhauser comorbidity index (ECI), and the Clinical Classification Software (CCS). The severity-adjustment models for mortality prediction in patients with acute stroke were developed using logistic regression, decision tree, neural network, and support vector machine methods. The most common comorbid disease in stroke patients were hypertension, uncomplicated (43.8%) in the ECI, and essential hypertension (43.9%) in the CCS. Among the CCI, ECI, and CCS, CCS had the highest AUC value. CCS was confirmed as the best severity correction tool. In addition, the AUC values for variables of CCS including main diagnosis, gender, age, hospitalization route, and existence of surgery were 0.808 for the logistic regression analysis, 0.785 for the decision tree, 0.809 for the neural network and 0.830 for the support vector machine. Therefore, the best predictive power was achieved by the support vector machine technique. The results of this study can be used in the establishment of health policy in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.88-95
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• 2018

Maintainability indicates how easily a system can be restored to the normal state when a system failure occurs. Systems developed to have high maintainability can be competitive due to reduced maintenance time, workforce and resources. Quantification of the maintainability is possible in many ways, but only after prototype production or with historical data. As such, the graph theory and 3D model data have been used, but there are limitations in management efficiency and early use. To solve this problem, we studied the maintainability index of weapon systems using SysML-based modeling and simulation technique. A SysML structure diagram was generated to simultaneously model the system design and maintainability of system components by reflecting the maintainability attributes acquired from the system engineering tool. Then, a SysML parametric diagram was created to quantify the maintainability through simulation linked with MATLAB. As a result, an integrated model to account for system design and maintainability simultaneously has been presented. The model can be used from early design stages to identify components with low maintainability index. The design of such components can be changed to improve maintainability and thus to reduce the risks of cost overruns and time delays due to belated design changes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.167-174
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• 2019

The propose od this study was to examine the extent of using physical restraint on elderly patients (over 65 years old) and who were patients in long-term care hospitals. The data was collected, from March 3 2018 to March 29 2018, from the electronic nursing records by using a recording tool, and clinical observation was also used for assessing the use of physical restraint and the related factors. Descriptive statistics, Pearson correlation coefficients and logistic regression were then performed. The usage rate for physical restraints in long-term care hospital was 83.7%, and the most common type of physical restraint was side rails. The use of physical restraints showed a positive correlation with the fall risk scores and a negative correlation with the MMSE. Logistic regression analysis showed that the Fall Risk Score (OR=1.02, 95% CI=1.01~1.03), MMSE (OR=0.94, CI=0.88~0.99) and the use of medical devices (OR=0.80, 95% CI=0.65~0.98) were related with using physical restraints. Therefore, it was confirmed that physical restraint was used in cases of a high risk of falling, severe cognitive impairment and the use of complex and fragile medical devices to treat the patient. Clinical nursing practice should be changed so that treatment alternatives can be applied for elderly patients rather than using too many physical restraints.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.465-473
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• 2019

This paper is meaningful as the first case where a 4 - sided hull-fixed phased array radar was installed on a mast separated from Korea and the alignment was verified. The mechanical alignment method was studied for accurately mounting two separate masts for naval ships and the 3D scanner for alignment. Hull-fixed phased array radar uses very high frequency, so the short wavelength can cause a phase difference of the device due to the small positional error. Since the array antenna is fixed with the hull, it has higher accuracy control than the rotary radar for 4 array surfaces. The study describes a method of checking the flatness of two radar masts manufactured at a factory, a method of aligning masts in a shipyard, and a method of aligning four array pad mounting surfaces. As a tool for this, a 3D laser scanner and a software-based method for comparing survey results with 3D CAD are used. This paper is meaningful as the first example of installing a four-sided hull-fixed phased array radar on a separate mast from a Korean naval ship and deriving a mechanical alignment method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.303-312
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• 2018

The university facility is made up of multiple buildings and has many maintenance items. In addition, administrative constraints need to be handled within a limited period. Most maintenance work is small scale and multi-work construction, such as waterproofing, needs to be organized. The facility manager makes annual unit price contract with a maintenance company and carries out the maintenance work. On the other hand, delay and rework is occurring because existing maintenance work performed without scheduling based on the manpower input. This study proposed a scheduling model that can support the facility manager to manage maintenance works of multiple university facilities at the program level. The model consists of three stages in order. In object analysis, details of the maintenance items were analyzed and the quantity is calculated based on the quantity takeoff sheet. In resource analysis, the craftsmen and construction period of detailed works are derived for the effective input of craftsmen. In scheduling, the priority of each work and the optimal manpower input are derived. The optimal schedule is selected according to the goodness of fit. The applicability and effectiveness of the prototype was evaluated through a case study and interviews with case participants. The model was found to be an effective tool to support the scheduling of maintenance works for the facility manager.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.910-917
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• 2018

This paper describes the developments to improve the feeling and safety of the remote control system of unmanned vehicles. Generally, in the case of the remote control systems, a joystick-type device or a simple steering-wheel are used. There are many cases, in which there are operations without considering the feedback to users and driving feel. Recently, as the application area of the unmanned vehicles has been extended, the problems caused by not considering the feedback are emphasized. Therefore, the need for a force feedback-haptic control arises to solve these problems. In this study, the force feedback-haptic control algorithm considering the vehicle parameters is proposed. The vehicle parameters include first the state variables of dynamics, such as the body side-slip angle (${\beta}$) and yawrate (${\gamma}$), and second, the parameters representing the driving situations. Force feedback-haptic control technology consists of the algorithms for general and specific situations, and considers the situation transition process. To verify the algorithms, a simulator was constructed using the vehicle dynamics simulation tool with CAN communication environment. Using the simulator, the feasibility of the algorithms was verified in various scenarios.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.158-165
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• 2019

Although evaluation of writing disabilities identification and timely intervention are required, clinicians adopt a manual scoring method and there is a possibility of error due to subjective evaluation. In this study, the size ratio and position of letters are digitized and quantified through image processing of offline handwritten characters. We tried to evaluate objectively and accurately the performance of writing through comparison with existing methods. From November 12th to 16th, 2018, 20 adults without neurological injury were selected. They used a pencil to follow the 10 words, 2 sentence stimuli after keeping the usual habit, and we collected the writing test data. The results showed that the height of the word was 1.2 times larger than the width and it tilted to the lower left. The spacing interval was 9mm on average. In the Paired T test, a high correlation was showed between our system and existing methods in the word and sentence 2. This demonstrated the possibility as a testing tool. This study evaluated objectively and precisely writing performance of offline handwritten characters through image processing and provided preliminary data for performance standards. In the future, it can be suggested as a basic data on writing diagnosis of various ages.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.863-871
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• 2018

Existing vulnerability analysis tools are prone to missed detections, incorrect detections, and over-detection, which reduces accuracy. In this paper, cross-checking based on a vulnerability detection method using static and dynamic analysis is proposed, which develops and manages safe applications and can resolve and analyze these problems. Risks due to vulnerabilities are computed, and an intelligent vulnerability detection technique is used to improve accuracy and evaluate risks under the final version of the application. This helps the development and execution of safe applications. Through incorporation of tools that use static analysis and dynamic analysis techniques, our proposed technique overcomes weak points at each stage, and improves the accuracy of vulnerability detection. Existing vulnerability risk-evaluation systems only evaluate self-risks, whereas our proposed vulnerability risk-evaluation system reflects the vulnerability of self-risk and the detection accuracy in a complex fashion to evaluate relative. Our proposed technique compares and analyzes existing analysis tools, such as lists for detections and detection accuracy based on the top 10 items of SANS at CWE. Quantitative evaluation systems for existing vulnerability risks and the proposed application's vulnerability risks are compared and analyzed. We developed a prototype analysis tool using our technique to test the application's vulnerability detection ability, and to show that our proposed technique is superior to existing ones.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.520-530
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• 2021

Objectives: This study aimed to identify the effects of music therapy on cognitive function, agitation, anxiety and depression in the elderly with dementia. Method: A comprehensive literature search was performed on PubMed, EMBASE, Cochrane Library, CINAHL, Web of Science, Google scholar and PsycINFO, for the period 2010 to 2019. In the meta-analysis, the standardized mean difference (Hedges' g) and 95% confidence interval were calculated as summary measure, and the random effect model and inverse variance method were applied using the RevMan 5.4 program. A total of 13 studies were included; all were determined to be acceptable, based on the Cochrane collaboration's tool for assessing risk of bias. Results: The effect size (Hedges' g) was 0.31 (95% CI: -0.02, 0.65) for cognition and -0.03 (95% CI: -0.17, 0.11) for agitation behavior as the primary outcomes, and 0.61 (95% CI: -1.17, -0.05) for anxiety and -0.44(95% CI: -0.88, 0.00) for depression as the secondary outcomes. Subgroup analysis by type of music intervention revealed that combined music therapy has a significantly increasing beneficial effect on cognition of dementia patients (g=0.45[95% CI: 0.03, 0.87]). Conclusion: Music therapy was determined to exert beneficial effects in reducing anxiety and depression, and combined music therapy demonstrated improved cognitive functions in elderly patients with dementia.