• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.20-28
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• 2015

A suitable monitoring method is necessary for successful policy implementation and its evaluation, required for effective prevention of abnormal fire occurrences. To do this, there were studies for applying control charts of quality management to fire occurrence monitoring. As a result, it was proved that more fire occurs in winter and its trend moves yearly-basis with some patterns. Although it has trend, if we apply the same criteria for each time, inefficient overreacting fire prevention policy will be accomplished in winter, and deficient policy will be accomplished in summer. Thus, applying different control limits adaptively for each time would enable better forecasting and monitoring of fire occurrences. In this study, we treat fire occurrences as time series model and propose a method for configuring its coefficients with ARIMA model. Based on this, we expect to carry out advanced analysis of fire occurrences and reasonable implementation of prevention activities.

• Journal of Korean Society for Quality Management
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• v.44 no.1
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• pp.167-180
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• 2016

Purpose: The problem for the traditional control chart is that it is unable to monitor the very small fraction of nonconforming and the underlying distribution is the normal distribution. $Z_p$ control chart is useful where it controls the vert small fraction on nonconforming. In this study, we will design the $Z_p$ control chart in order to use under non-normal process. Methods: $Z_p$ is calculated not by failure rate based on attribute data but using variable data. Control limit for non-normal $Z_p$ control chart is designed based on ${\alpha}$-risk calculated by cumulative distribution function of Burr distribution. ${\beta}$-risk, which is for performance evaluation, obtains in the Burr distribution's cumulative distribution function and control limit. Results: The control limit for non-normal $Z_p$ control chart is designed based on Burr distribution. The sensitivity can be checked through ARL table and OC curve. Conclusion: Non-normal $Z_p$ control chart is able to control not only the very small fraction of nonconforming, but it is also useful when $Z_p$ distribution is non-normal distribution.

• Journal of Fashion Business
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• v.12 no.3
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• pp.116-135
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• 2008

To investigate the actual distribution condition and clothing construction factors of the working clothes supplied to the Changwon national industrial complex, 5 major companies in machinery, automotive, industrial engineering, shipbuilding and rolling stock in the industrial complex located in Gyeongsangnam-Do were selected. The questionnaire designed for the research consisted of working clothes distribution policies in manufacturing industry and the actual conditions of the design facts, repair and maintenance of the working clothes, etc. The analysis of the clothing construction factors of the working clothes provided by 5 respondent companies were conducted in parallel. The results derived from the study were as follows: The basic types of working clothes were the blouson jacket and straight pants; safety equipments for manufacture were safety helmets, gloves, snickers, goggles, masks, ear caps, wristlets, leggings, apron, etc. The size-charts adopted by the participant companies were the small-medium-large and cm/inch measurement size systems. To solve wearer's dissatisfaction with the garment fit, certain clothing construction factors were used, e.g. strap bands and the elastic band on a waist band. The types of fabrics used for the working clothes were mainly polyester/cotton and polyester/rayon blended ones. Moreover, to provide with more air permeability to wearers, the warp knit material was used to construct the lining and the armpit or back bodice slits. Lock, two-thread chain, safety, overedge stitches were applied with flat, lap felled, French, superimposed, lapped, bound and edge finishing seams to construct the working clothes selected.

• Asian Spine Journal
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• v.12 no.6
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• pp.1053-1059
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• 2018

Study Design: Retrospective review. Purpose: To detect the effect of cannulated (poly-axial head) and solid (mono-axial head) screws on the local kyphotic angle, vertebral body height, and superior and inferior angles between the screw and the rod in the surgical management of thoracolumbar fractures. Overview of Literature: Biomechanics studies showed that the ultimate load, yield strength, and cycles to failure were significantly lower with cannulated (poly-axial head) pedicle comparing to solid core (mono-axial head). Methods: The medical charts of patients with thoracolumbar fractures who underwent pedicle screw fixation with cannulated or solid pedicle screws were retrospectively reviewed; the subjects were followed up from January 2011 to December 2015. Results: Total 178 patients (average age, $36.1{\pm}12.4years$; men, 142 [84.3%]; women, 28 [15.7%]) with thoracolumbar fractures who underwent surgery and were followed up at Hamad Medical Corporation were classified, based on the screw type as those with cannulated screws and those with solid screws. The most commonly affected level was L1, followed by L2 and D12. Surgical correction of the local kyphotic angle was significantly different in the groups; however, there was no significant difference in the loss of correction of the local kyphotic angle of the groups. Surgical correction of the reduction in the vertebral body height showed statistical significance, while the average loss of correction in the reduction of the vertebral body height was not significantly different. The measurement of the angles made by the screws on the rods was not significantly different between the cannulated (poly-axial head) and solid (mono-axial head) screw groups. Conclusions: Solid screws were superior in terms of providing increased correction of the kyphotic angle and height of the fractured vertebra than the cannulated screws; however, no difference was noted between the screws in the maintenance of the superior and inferior angles of the screw with the rod.

• Tunnel and Underground Space
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• v.32 no.1
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• pp.20-29
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• 2022

The existence of underground cavity should be considered in the assessment of georisk such as ground subsidence. Even if the shear strength of the ground around the cavity is known, it is difficult to accurately analyze the safety around the cavity due to the uncertainties related to geometric conditions such as the cavity size. In this paper, stability chart representing dimensionless stability constants was proposed based on the ground strength and geometric conditions. Numerical analysis had been carried out accounting for the stability constants such as the ground strength, the adhesion and friction angles, and the size and depth of the underground cavity. The proposed charts can help estimating the stability of ground with underground circular cavity.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.4
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• pp.79-90
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• 2021

This paper presents a study to reduce the effect of blast pressure on the blast valves installed in protection tunnels, where the shape of the tunnel entrance and the blast pocket is optimized based on the predetermined basic shape of the protective tunnels. The reliability of the numerical tunnel models was examined by performing analyses of mesh convergence and overpressure stability and with comparison to the data in blast-load design charts in UFC 3-340-02 (DoD, 2008). An optimal mesh size and a stabilized distance of overpressure were proposed, and the numerical results were validated based on the UFC data. A parametric study to reduce the blast overpressures in tunnel was conducted using the validated numerical model. Analysis was performed applying 1) the entrance slope of 90, 75, 60, and 45 degrees, 2) two blast pockets with the depth 0.5, 1.0, and 1.5 times the tunnel width, 3) the three types of curved back walls of the blast pockets, and 4) two types of the upper and lower surfaces of the blast pockets to the reference tunnel model. An optimal solution by combining the analysis results of the tunnel entrance shape, the depth of the blast pockets, and the upper and lower parts of the blast pockets was provided in comparison to the reference tunnel model. The blast overpressures using the proposed tunnel shape have been reduced effectively.

• Geomechanics and Engineering
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• v.31 no.5
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• pp.439-452
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• 2022

A forecast of slope behavior during catastrophic events, such as earthquakes is crucial to recognize the risk of slope failure. This paper endeavors to eliminate the significant supposition of predefined slip surfaces in the slope stability analysis, which questions the relevance of simple conventional methods under seismic conditions. To overcome such limitations, a methodology dependent on the slip line hypothesis, which permits an automatic generation of slip surfaces, is embraced to trace the extreme slope face under static and seismic conditions. The effect of earthquakes is considered using the pseudo-static approach. The current outcomes developed from a parametric study endorse a non-linear slope surface as the extreme profile, which is in accordance with the geomorphological aspect of slopes. The proposed methodology is compared with the finite element limit analysis to ensure credibility. Through the design charts obtained from the current investigation, the stability of slopes can be assessed under seismic conditions. It can be observed that the extreme slope profile demands a flat configuration to endure the condition of the limiting equilibrium at a higher level of seismicity. However, a concurrent enhancement in the shear strength of the slope medium suppresses this tendency by offering greater resistance to the seismic inertial forces induced in the medium. Unlike the traditional linear slopes, the extreme slope profiles mostly exhibit a steeper layout over a significant part of the slope height, thus ensuring a more optimized solution to the slope stability problem. Further, the susceptibility of the Longnan slope failure in the Huining-Wudu seismic belt is predicted using the current plasticity approach, which is found to be in close agreement with a case study reported in the literature. Finally, the concept of equivalent single or multi-tiered planar slopes is explored through an example problem, which exhibits the appropriateness of the proposed non-linear slope geometry under actual field conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.259-266
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• 2023

Global climate change is increasing, and the damage and scale of localized torrential rains are increasing. Pre-flood analysis simulation results should be derived from rainfall data through rainfall forecasts to prevent flood damage. In addition, it is necessary to control the use and management of flood response disaster prevention facilities through immediate decision-making. However, methods using spills and flood models such as XPSWMM and GATE2018 are limited due to professional usability and complex analytical procedures. Prototype (flood disaster prevention facility simulator) of this study is developed by calculating rainfall (short-term and long-term) using CBD software development methods. It is also expected to construct administrator and user-centric interfaces and provide GIS and visible data (graphs, charts, etc.).

• Journal of Chest Surgery
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• v.56 no.2
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• pp.120-125
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• 2023

Background: Multiple rib fractures are common in blunt chest trauma. Until recently, most surgical rib fixations for multiple rib fractures were performed via open thoracotomy. However, due to the invasive nature of tissue dissection and the resulting large wound, an alternative endoscopic approach has emerged that minimizes the postoperative complications caused by the manipulation of injured tissue and lung during an open thoracotomy. Methods: Our study concentrated on patients with multiple rib fractures who underwent surgical stabilization of rib fractures (SSRF) between June 2018 and May 2020. We found 27 patients who underwent SSRF using video-assisted thoracoscopic surgery. The study design was a retrospective review of the patients' charts and surgical records. Results: No intraoperative events or procedure-related deaths occurred. Implant-related irritation occurred in 4 patients, and 1 death resulted from concomitant trauma. The average hospital stay was 30.2±20.1 days, and ventilators were used for 12 of the 22 patients admitted to the intensive care unit. None of the patients experienced major pulmonary complications such as pneumonia or acute respiratory distress syndrome. Conclusion: Minimally invasive rib stabilization surgery with the assistance of a thoracoscope is expected to become more widely used in patients with multiple rib fractures. This method will also assist patients in a quick recovery.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5C
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• pp.323-331
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• 2006

It is a recent worldwide trend that erosion characteristics of soil, the resistance factor against scour, are quantified and considered in the estimation of scour depths in fine-grained soils. As part of the efforts, local erosion characteristics on fine-grained soils of the West Coast area are analyzed through scour rate experiments, where a lot of sea-crossing long-span bridges are planned and being constructed in recent years. Four sites including Incheon Bridge, Choji Bridge, Hwankyung Bridge, and Janghang area are finally selected for this study and the scour rate tests are performed using 34 undisturbed soil samples from the sites. The critical shear stresses which represent erodibility of the soil tend to be proportional to the undrained shear strength values. The relative ability of cohesive fine-grained soils to resist erosion is assumed to be higher than that of noncohesive soils. Quantified local erosion characteristics of fine-grained soils in the West Coast area are presented in forms of charts showing relationships between scour rates and shear stresses, and suggested as basic data for the estimation of scour depths and design of bridge foundations in the West Coast area.