• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.3
• /
• pp.147-155
• /
• 2016

Industry 4.0's goal is the 'Smart Factory' that integrates and controls production process, procurement, distribution and service based on the fundamental technology such as internet of the things, cyber physical system, sensor, etc. Basic requirement for successful promotion of this Industry 4.0 is the large supply of semiconductor. However, company I who produces dicing blades has difficulty to meet the increasing demand and has hard time to increase revenue because its raw material includes high price diamond, and requires very complex and sensitive process for production. Therefore, this study is focused on understanding the problems and presenting optimal plan to increase productivity of dicing blade manufacturing processes. We carried out a study as follows to accomplish the above purposes. First, previous researches were investigated. Second, the bottlenecks in manufacturing processes were identified using simulation tool (Arena 14.3). Third, we calculate investment amount according to added equipments purchase and perform economic analysis according to cost and sales increase. Finally, we derive optimum plan for productivity improvement and analyze its expected effect. To summarize these results as follows : First, daily average blade production volume can be increased two times from 60 ea. to 120 ea. by performing mixing job in the day before. Second, work flow can be smoother due to reduced waiting time if more machines are added to improve setting process. It was found that average waiting time of 23 minutes can be reduced to around 9 minutes from current process. Third, it was found through simulation that the whole processing line can compose smoother production line by performing mixing process in advance, and add setting and sintering machines. In the course of this study, it was found that adding more machines to reduce waiting time is not the best alternative.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.33 no.3
• /
• pp.1-19
• /
• 2020

Objectives: The purpose of this study is to assess the efficacy and safety of electroacupuncture for women with overactive bladder (OAB) comparing with sham- acupuncture, and electroacupuncture plus drugs. Methods: We searched 8 databases upto May 26, 2020. Randomised controlled trials (RCTs) were eligible. The risk of bias was assessed by two independent authors using the Cochrane risk of bias tool. Study outcomes were calculated by standardized mean differences (SMD) with 95% confidence intervals (Cls) and mean differences (MD) with 95% Cls. Results: Of 146 screened, 5 RCTs were included. Number of participants per study ranged from 5 to 57. The combined results showed that electroacupuncture (EA) may be more effective than sham acupuncture or enhance solifenacin succinates in improving Overactive Bladder Symptom Score (OABSS) and urination frequency of 24 h. However, more trials with high quality and larger sample sizes will be needed to provide sufficient evidence. Only 5 of 187 OAB patients from the included studies reported mild adverse reactions related to EA, therefore, electroacupuncture is safe for treating OAB. Conclusions: Electroacupuncture might have effect in decreasing urination frequency of 24 h and OABSS. However, the evidences ins in sufficient to show the effect using electroacupuncture alone or additional effect to drugs in treating OAB.

• Journal of Oriental Neuropsychiatry
• /
• v.28 no.1
• /
• pp.1-13
• /
• 2017

Objectives: The purpose of this study is to investigate the trends in acupuncture research on Internet addiction disorder. Methods: Clinical research papers on acupuncture treatment were searched and selected. Seven databases, including English, Chinese, Japanese, and Korean databases, were searched systematically. Non-clinical, non-acupuncture, and unpublished studies were excluded. The characteristics of the included articles were described, and these articles were assessed by the Risk of Bias (RoB) tool or the Risk of Bias Assessment for Non-randomized Studies (RoBANS) tool. Results: Ten clinical studies on Internet addiction disorder were finally selected, and all of these studies were published in China. The electroacupuncture (EA) method was used in most of the acupuncture treatment studies. Most of the psychotherapy studies used cognitive behavioral therapy (CBT) in the control group. Most of the studies showed effective results. The results of this study suggest that the combination of acupuncture and psychotherapy is more effective than either treatment modality alone. However, the quality of these clinical studies was low. Conclusions: According to this study, acupuncture treatment seems to have excellent effects in Internet addiction disorder. However, the quality of most studies was low. Therefore, higher quality research on Internet addiction disorder is required.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.10a
• /
• pp.74-80
• /
• 1999

Work roll wear in the cold rolling of mild steel strip is strongly affected by rolling materials, rolling conditions such as roll arrangement in the cold rolling mill and lubrication. The tests were performed to find the effects of roll arrangement n the cold rolling mill on the work roll wear under the same lubricating conditions. The obtained results are as follows:If the distance of cold rolling is about 60km, the surface roughness of its was reduced by half(Ra 0.49${\mu}{\textrm}{m}$) and Pc(peak count) also was decreased to 60 ea/cm.It is easier for CC(Continuous casting) to make a slip on rolling than IC(Ingot casting). It is due to surface mirror in which first residual product appears and iron powder included Al2O3 is sticked. Because bending degree of 4Hi-rolling mill is higher than 6Hi-rolling mill, the first surface mirror was occurred to its center-point which is loaded strongly. 6Hi-rolling mill shape-controlled by intermediate roll doesn't need the initial crown to work roll. Therefore, fatigue and wear would appear a little bit.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.2
• /
• pp.37-44
• /
• 2006

The purposes of this study were to analyze and compare EMG activities of the pectoralis major, biceps brachii, triceps brachii, and brachioradialis muscles during biceps curls using a VRT device and an elastic tubing. Fifteen male college students were recruited as subjects and they performed 10-RM and 20-RM biceps curls. For each load and device condition, the mean and peak normalized EMG levels during different phases of a biceps curl were computed. For each load and phase, paired t-test (p.05) was used to find the significant difference between two devices. ANOVA with repeated measures was also used to find the significant difference among phases in terms of EMG values for each muscle. For each load and device condition, the peak and mean EMG levels during different phases of a biceps curl were computed The significant differences between devices were found in biceps brachii for EA, MD, LD phases, and triceps brachii muscles for all phases, respectively. However, no differences were found among phases for any muscle. This indicated that elastic band could have a similar characteristics of VRT. High antagonistic muscle activity as a function of injury prevention which found particularly in VRT device may suggest that elastic tubing can be a safer training device than VRT. This also imply that elastic tubing could be very effective as a home exercise tool for rehabilitation patients and elderly people.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.7
• /
• pp.19-25
• /
• 2014

In the LED lighting applications, because LED packages are the origin of heat generation, there are thermal design problem on heat sinks. In the thermal design, it is important to consider the total volume and the total weight of heat sink simultaneously. In this study, an Al 6063 heat sink was optimized using Computational Fluid Dynamics(CFD) simulation tool for the cooling of 30W LED module, and then the cooling performance and the total weight of heat sinks with Al 6063 and Thermal Conductive Polycarbonate(TCP) were compared under the same conditions. As the result of simulation, an Al 6063 heat sink was optimized with 22 ea. of fins and 1.6 mm of fin thickness. LED Junction Temperature of the TCP Heat Sink was $5.6^{\circ}C$ higher, but total weight of it was 47 % less than the Al 6063.

• Applied Chemistry for Engineering
• /
• v.30 no.5
• /
• pp.556-561
• /
• 2019

In this study, the physical and chemical analyses of petroleum residues (pyrolized fuel oil, PFO) were conducted and major components were selected to investigate their fire and explosion characteristics. Major component distribution areas of the PFO were identified via the GC-SIMDIS and MALDI-TOF analyses. In addition, the qualitative analysis of major component distribution areas was performed by GC-MS analysis. Major components of pyrolysis residue were selected based on the results of various analyses such as EA, SARA and TGA. As a result, benzene, toluene and xylene were selected as major components. Finally, the process hazard analysis software tool (PHAST) analysis was performed to investigate the range of maximum damage effect in case of fire and explosion. Toluene presented the highest risk due to the radiation effect of $227kW/m^2$ and 118 m in the case of jet fire. Xylene and benzene showed the maximum radiant heat values of 114 and $151kW/m^2$, respectively. It was also confirmed from the analysis of pasquill stability and wind speed that the radiant heat increased up to 55% according to wind speed in benzene, which was considered to be a main factor increasing the influence range.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.4
• /
• pp.16-22
• /
• 2013

In this study, we propose the method of optimally changing material of BIW for minimizing weight while satisfying vehicle requirements on static stiffness. First, we formulate a material selection optimization problem. Next, we establish the CAE procedure of evaluating static stiffness. Then, to enhance the efficiency of design work, we integrate and automate the established CAE procedure using a commercial process integration and design optimization (PIDO) tool, PIAnO. For effective optimization, we adopt the approach of metamodel based approximate optimization. As a sampling method, an orthogonal array (OA) is used for selecting sampling points. The response values are evaluated at the sampling points and then these response values are used to generate a metamodel of each response using the linear polynomial regression (PR) model. Using the linear PR model, optimization is carried out an evolutionary algorithm (EA) that can handle discrete design variables. Material optimization result reveals that the weight is reduced by 44.8% while satisfying all the design constraints.

• Informatization Policy
• /
• v.18 no.1
• /
• pp.73-99
• /
• 2011

The Korean military has developed and operated computer, network, communication technologies as well as war game models to strengthen the national defense M&S continuously. In particular, lots of projects for developing models for drill/training, analyses, and acquired fields are being conducted in the military. However, it needs to look into the actual conditions and seek for strategies to develop the national defense M&S. First of all, in the field of war games, various national defense architectures have been built, including war and information environment architectures starting from the resource architecture in 2006. However, the function of drill and training is limited, so additional war game architectures are required to be built. To build joint war game architectures available as an effective verification tool to implement plans of the national defense and war architectures, this study examines the actual conditions of the current war game systems and suggested building joint war game architectures.

• Journal of the Korean Solar Energy Society
• /
• v.35 no.2
• /
• pp.93-101
• /
• 2015

Zero energy building is a self sufficient building that minimizes energy consumption through passive elements such as insulation, high performance window system and installing of high efficiency HVAC system and uses renewable energy sources. The Korea Government has been strengthening the building energy efficiency standard and code for zero energy building. The building energy performance is determined by the performance of building envelope. Therefore it is important to optimize facade design such as insulation, window properties and shading, that affect the heating and cooling loads. In particular, shading devices are necessary to reduce the cooling load in summer season. Meanwhile, BIPV shading system functions as a renewable energy technology applied in solar control facade system to reduce cooling load and produce electricity simultaneously. Therefore, when installing the BIPV shading system, the length of shadings and angle that affect the electricity production must be considered. This study focused on the facade design applied with BIPV shading system for maximizing energy saving of the selected standard building. The impact of changing insulation on roof and walls, window properties and length of BIPV shading device on energy performance of the building were investigated. In conclusion, energy consumption and electricity production were analyzed based on building energy simulations using energyplus 8.1 building simulation program and jEPlus+EA optimization tool.