• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.11
• /
• pp.483-490
• /
• 2016

Automobile door latch is a fine design and assembly techniques are required in order to produce them in a small component assembly shape such as a spring, injection products, a small-sized motor. The door latch is fixed to not open the door of the car plays an important role it has a direct impact on the driver's safety. In this study, during trimming of the terminals of the connector main components of the car door latch, reduce rollover and conducted a research to find a suitable effective shear surface. Using the Taguchi method with orthogonal array of Finite Element Analysis and optimal Design of Experiments were set up parameters for the shear surface quality of the car door latch connector terminals. The design parameters used in the analysis is the clearance, the radius, and the blank holding force, the material of the connector terminal is a C2600. Trimming process optimum conditions suggested by the analysis has been verified by experiments, the shear surface shape and dimensions of a final product in good agreement with forming analysis results.Taguchi method from the above results in the optimization for the final rollover and effective shear surface improved for a vehicle door latch to the connector terminal can be seen that the applicable and useful for a variety of metal forming processes other than the trimming process is determined to be applicable.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.186-192
• /
• 2016

The purpose of this study is to examine how Korean dance affects middle-aged women by acting as a cultural mediator. A qualitative approach was taken in order to best achieve the purpose of this study. The data used in this study were collected from Feb 10th to April 1st, 2016, using in-depth interviews. The results are as follows; firstly, on an emotional level, the middle-aged women participating in Korean dance as a cultural mediator, feel a sense of self-achievement and social belonging, as well as experiencing an improvement in their psychological stability by resolving their depression. Those who had lost their sense of autonomy and productivity were able to recover some of their self-esteem through this activity. Secondly, in terms of their activity, the Korean dance enabled the ladies to exercise their poorly used muscles by strengthening their gross and fine motor skills through the movements associated with the Korean traditional music. This allowed them to ease their chronic physical pain and it can be considered that their overall exercise function was increased by expanding their exercise radius. Third, in the cognitive area, it was possible for them to revive their happy memories by listening to the music which was loved by their preceding generations. This is because the melody of familiar Korean music provides them with the chance to remember their former days. Lastly, in the social area, the Korean dance allowed the middle-aged women to accept themselves through music and movement, as well as playing the role of a mediator which enabled them to overcome their isolation and the conflicts they face in their social relations. In addition, they achieved self-realization by reconnecting with the regional community through the Korean dance performances, which they learned as social community members.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.4
• /
• pp.117-122
• /
• 2018

A large-capacity three-phase system air conditioner recently includes an inverter circuit to reduce power consumption. The inverter circuit uses a DC voltage that comes from DC-link power capacitor with the function of rectifying, which means AC voltage to DC voltage using a diode. An electrolytic capacitor is generally used to satisfy the voltage ripple and current ripple conditions of a DC-link power capacitor used for rectifying. Reducing the capacitance of the capacitor decreases the size, weight, and cost of the circuit. This paper proposes an algorithm to reduce the input ripple current by combining the minimum point estimation phase locked loop (PLL) phase control and the average voltage d axis current control technique. When this algorithm was used, the input ripple current decreased by almost 90%. The current ripple of the DC-link capacitor decreased due to the decrease in input ripple current. The capacitor capacity can be reduced but the electrolytic capacitor has a heat generation problem and life-time limitations because of its large equivalent series resistance (ESR). This paper proposes a method to select a film capacitor considering the current ripple at DC-link stage instead of an electrolytic capacitor. The capacitance was selected considering the voltage limitation, RMS (Root Mean Square) current capacity, and RMS current frequency analysis. A $1680{\mu}F$ electrolytic capacitor can be reduced to a $20{\mu}F$ film capacitor, which has the benefit of size, weight and cost. These results were verified by motor operation.

• Journal of environmental and Sanitary engineering
• /
• v.7 no.2
• /
• pp.1-10
• /
• 1992

Since 1960's along with industrialization and urbanization, economic growth has been . achieved, however, at the same time, environmental condition has been seriously deteriorated. . Currently, volume of wastewater has been increasing at annual rate of 7% in sewage and 20% in industrial wastewater. However, the nation's sewage treatment serves only 33% of the municipal wastewater as of 1991. Major portion of air pollutants comes from combustion of oil and coal which comprise 81% of total energy use and emission gases from motor vehicles increasing at an accelerated rate. It is known that Korea generates the highest amount of waste per capta. Nevertheless, it is not sufficient to reduce the volume of waste by means of resources recovery and recycling. Recognizing the importance of global environmental problems such as ozone layer depletion, global warming and acid rain, international society has been making various efforts since the 1972 Stockholm conference. In particular, it is expected that the Rio conference which has adopted the Rio declaration and Agenda 21 will form a crucial turning point of the emerging new world order after the Cold War confrontation. To cope with such issues as domestic pollution and global environmental problems, the fundamental national policy aims at harmonizing "environmental protection and sustainable development". The Ministry of Environment has recently set up a mid-term comprehensive plan which includes annual targets for environmental protection. According to the government plan, gradual improvement of various environmental conditions and specific measures to achieve them is planned in time frame. Additional sewage treatment plants will be constructed in urban areas with the target to treat 65% of the nation's municipal sewage by 1996. Supply of clean fuels such as LNG will also be expanded starting from large cities as a cleaner substitute energy for coal and oil. In parallel with expansion of LNG, emphasis will be placed on installation of stack monitoring system. Due to the relatively limited land, government's basic policy for solid waste treatment is to develop large scale landfill facilities rather than small sized ones. Thirty three regional areas have been designated for the purpose of waste management. For each of these regions, big scale landfill site is going to be developed. To increase the rate of waste recycling the government is planning to reinforce separate collection system and to provide industries with economic incentives. As a part of meeting the changing situation on global environmental problems after UNCED, and accommodation regulatory measures stipulated in the global environmental conventions and protocols, national policy will try to alter industrial and economic structure so as to mitigate the increasing trends of energy consumption, by encouraging energy conservation and efficiency. In this regard, more attention will be given to the policy on the development of the cleaner technology. Ultimately, these policies and programs will contribute greatly to improving the current state of national public health.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.10
• /
• pp.499-504
• /
• 2017

A Mobile Radio Wave Measurement System (MRWMS)is a vehicle-mounted system designed to be operating in a single mission. The mission characteristic for mobile measurement requires mobility. For this, we must consider the arrangement and embedded method of MRWMS's antennas. In this paper, we described the measurement method design of direction detecting accuracy for MRWMS and designed the direction finding antenna mast capable of rotating itself by using a slip ring without turntable for Direction Finding (DF) accuracy test. As we removed the dependency of a limited local area by designing a measurement method of direction detecting accuracy, Equipment Under Test (EUT) zero-Adjustment and mounted process shortened. So, we the reduced production costs. We expect an improved cable loss value by shortening the RF cable length in accordance with our design. In addition, due to the same phenomenon, the entire system is lighter and the mobility is improved.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.12
• /
• pp.1285-1292
• /
• 2011

The characteristics of a semiconductor chiller system with EEV have been experimentally studied. Three experiments on temperature changes (increase and decrease), load variation, and control precision were conducted to investigate the operating characteristics of the semiconductor chiller. The power consumption was 8.9 kW during increase in temperature. The required time was 37.5 min for CH1 and 39.5 min for CH2. Moreover, the time required for falling temperature was 26.5 min. The control precision for partial load operation was relatively low compared to that of a full load operation. In addition, the CH2 equipped with a step motor showed better control precision. The power consumed by the chiller for process cooling water was 1.8 kW, which was one-half of that consumed during the refrigeration cycle. The objective of this study is to provide an optimal control guideline for the semiconductor chiller design.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.8
• /
• pp.200-207
• /
• 2016

The automotive seat is an important component that moves in sync with the driver and is actively being developed with various new functions. The aim of this work is to develop a lightweight seat cushion extension module using a lightweight material. To this end, a structural strength analysis, vertical strength test, and durability test were conducted. In the structural analysis, the maximum value of deformation under vertical load was 4.98 mm at the front of the upper panel. The maximum stress was approximately 105 MPa, which occurred at the point of contact between the upper and lower panels of the module. The vertical strength test showed a maximum vertical deformation of 5.31 mm under a vertical load, which differed from the analysis results by approximately 6.45%. The structural safety of the product was verified by the fact that it showed no harmful deformation or damage during operation after the vertical strength test and a durability test for 20,000 cycles. Furthermore, the use of engineering plastics made it possible to reduce the weight by approximately 30% compared to existing products. The lack of damage after tests verified the passenger safety, strength, and rigidity of the product. The results are expected to be applied for improving environmental and fuel efficiency regulations and preventing accidents due to driver fatigue. The applications of this module could be expanded various types of vehicles, as well as other industries in which eco-friendly and lightweight materials are used.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.608-613
• /
• 2019

NOx (Nitrogen oxide) in the exhaust gas from vehicle engines is considered one of the most harmful substances in air pollution problems. NOx is made when combustion occurs under high temperature conditions and EGR (exhaust gas recirculation) is normally used to lower the combustion temperature. As the EGR ratio increases, the NOx level becomes low, but a high EGR ratio makes the combustion unstable and causes further air pollution problems, such as CO and unburned hydrocarbon level increase. This study showed that fuel droplets could move more freely by the radiation of sonic wave for the stable combustion. In addition, the engine performance improved with increasing EGR ratio. As a basic study, the effect of sonic wave radiation on the velocity of fuel droplets was studied using CFD software. The results showed that the velocity of small droplets increased more under high frequency sonic wave conditions and the velocity of the large droplets increased at low frequency sonic wave conditions. In addition, an engine analysis model was used to study the effects of the increased combustion stability. These results showed that a 15% increase in EGR ratio in combustion resulted in a 45% decrease in NOx and a 10% increase in thermal efficiency.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.9
• /
• pp.596-603
• /
• 2020

'Electro-Mechanical Brake (EMB) is a novel braking system for automobiles and railway vehicles, and research in this area is actively underway. The current braking system for railway vehicles generates a braking force using a pneumatic cylinder, but the EMB system generates the force through a combination of an electric motor and gears. In this study, the design of an EMB system that meets the domestic standards was conducted through the finite element modeling and fatigue analysis of an eccentric rotating shaft-based EMB system capable of generating a high clamping force. At this time, to improve the accuracy of fatigue analysis, three types of fatigue test specimens, which were subjected to the same heat treatment as the materials used in the prototype, were produced, and the fatigue tests were performed for each material. The fatigue properties (S-N curves) were obtained from the fatigue test results for each material and reflected in the analysis model. The results of fatigue analysis confirmed that the design of the EMB prototype could satisfy the maximum commercial braking/relaxation of 530,000 times, which was the endurance life condition for domestic railway vehicles. In addition, based on this design, a prototype will be manufactured, and endurance testing will be completed to demonstrate the durability characteristics of the developed prototype.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.5
• /
• pp.269-274
• /
• 2013

To proportionally control the electronic valve position of the actuator, we designed and fabricated PCU, CPT, and rotary absolute optical encoder for the detection of absolute angular position in the actuator. We also designed and constructed the test system by using DAQ hardware and Labview. We designed PCU to convert 1-5 V, 0-5 V, 0-10 V, 2-10 V voltage signals and 4-20 mA current signals to the voltage signals in the common 0.5-2.5 V range. We designed CPT to output 4-20 mA current signals corresponding to the valve positions based on the PWM signal input from the MCU. We also designed 20 bit optical encoder by using infrared LED and infrared transistor and made the serial communication with the main board possible. When we tested PCU and CPT with DAQ hardware and Labview software, they operated correctly with the small errors within ${\pm}0.003$ V and ${\pm}0.01$ mA, respectively, showing that our actuator has the excellent performance to employ as the industrial proportional-valve-actuator. The resolution of the encoder was $11.25^{\circ}$ and the maximum revolution to detect was 32,768.