• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.433-438
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• 2001

This study is performed to evaluate hand-arm vibration syndrome(HA VS) of the workers in swaging process. Vibration measurement and assessment of human exposure are based on the international standard(ISO 5349). Triaxial acceleration of each operation and exposure time are measured to predict the periods before finger blanching, As results, it is found that acceleration is concerned with the diameter of pipes in swaging process, and also found that combined work is more harmful than a single operation.

• Speech Sciences
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• v.7 no.2
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• pp.225-234
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• 2000

This paper describes the fixed-point DSP implementation of a CELP(Code-excited linear prediction)-based speech coder. The effective realization methodologies to maximize the utilization of the DSP's architectural features, specifically parallel movement and pipelining are also presented together with the implementation results targeted for the ITU-T standard G.723.1 using Motorola DSP56362. The operation of the implemented speech coder is verified using the test vectors offered by the standard as well as using the peripheral interface circuits designed for the coder's real-time operation.

• Journal of the Korean Society of Safety
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• v.35 no.1
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• pp.12-17
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• 2020

This paper analyzes functions of component parts of D-Urban Railway's door system along with operation obstacle risks on frequency(the number of occurrences/year) and severity(delay time/the number of occurrences). Based on this, the paper presents improvements and current system's problems after obstacle risks of EMU and door system are appled. The obstacle of door system causes corrosion of main parts such as DCU due to heat problem of operation environment, problems of maintenance methods and deterioration. DCUs on PCBs with more than 50% pattern corrosion cause problems. Even though the number of door system's obstacle occurrences for the last 5 years is 42, along with 104 minutes of operation obstacle, EMU operation obstacle risk is low(Level 1), which indicates there is limit in matrix of railway risks presented by the standard of railway safety management system. Therefore, it is necessary to have railway risk matrix suitable for the field. Finally, the paper deducts the obstacle risks through frequency and severity. Since 2017 when the risks of EMU and door system's obstacle, that of EMU has been 24(47% reduced) and that of door system has been average 9.5 per year(23% reduced).

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.490-497
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• 2011

When operating Express and Standard trains, which run with two different scheduled time, in a single line with limited number of side tracks for overtaking standard trains, it is required to have various modeling methodologies and simulations in order to calculate an optimum headway to maximize the capacity of the line with the best scheduled time. Especially it is inevitable that following trains have to slow down or stop in the middle of their operations due to the preceding trains, in case it is inappropriate controlled about either in which station an overtaking should be taken or how long it should be. This study is to analyze TPS data which have been produced with a simulation program which the team has invented to optimize Express and Standard mixed traffic plan and to introduce an algorism which shows detected conflict data, calculates appropriate dwell time after getting overtaken and helps to decide stations for overtaking.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.220-231
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• 1991

The main purpose of this research is to standardize the logging operation with special reference to the net working time for thinning. This study was carried out to obtain the standard working method and working technique for Korean logging operation through the comparison of the present Korean working method and the German standard working method 1. The net working time devided into work elements showed little difference between those two working methods. 2. From the correlation analysis, net working time was significantly correlated with breast height diameter, the dependant variable, with the highest correlation coefficient in each species. 3. Total working time increases by 11 to 13 seconds to every 1 centimeter increase in breast height diameter from i to 16 centimeter. 4. The result of this study concluded that the German working method is recommended for improving the labour problems in the forest operation due to high wages and lack of manpower gradually increasing from now in Korea. In addition to the application of this standard working method, the technical training for the method should be done to the workers for improving the productivity.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.117-123
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• 2021

This study aims to analyze working hours of sprinkler heads when a fire occurs at an indoor gymnasium while sprinkler heads are installed in division of standard response type, special response type, and earlier response type. The fire scenario was designed under the assumption that the fire started from overheating of a heater in the indoor gymnasium has transferred on to a couch to spread. The analysis on the operation time of the standard response type sprinkler head, the special response type sprinkler head and the early response sprinkler head was conducted. The result showed that, in case of fire in a gymnasium, the time for opening of the heat sensor due to the heat from the fire varies by the type of the sprinkler head. When a special response type sprinkler is installed, it worked below the assessment standards. When an early response sprinkler head is installed, it worked appropriately according to assessment standards. Based on the results, we found that sprinkler heads will work properly when installed according to design relevant to laws and regulations. This means that there is a limit in installation of sprinkler heads based on the existing law-based design as for indoor gymnasiums. Again, we conclude that if sprinkler heads are installed based on design made through laws and regulations, more time will be needed for operation, making it highly likely to fail to stop a fire at an earlier point of time.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.2
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• pp.150-156
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• 2003

The IEEE 802.11 MAC (Media Access Control) Protocol supports two modes of operation, a random access mode for nonreal-time data applications processed by Distributed Coordinated Function (DCF), and a polling mode for real-time applications served by Point Coordinated Function (PCF). It is known that the standard IEEE 802.11 is insufficient to serve real-time traffic. To provide Quality of Service (QoS) of real-time traffic, we propose the Downlink-first scheduling with Earliest Due Date (EDD) in Contention Free Period (CFP) with suitable admission control. The capacity and deadline violation probability of the proposed system is analyzed and compared to the standard pair system of downlink and uplink. Analytical and simulation results show that the proposed scheme is remarkably efficient in view of the deadline violation probability.

• Journal of the Korean Dietetic Association
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• v.12 no.2
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• pp.157-171
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• 2006

This study was intended to suggest HACCP-based standard recipe for bellflower roots, classified as no thermal cooking process, served in a university foodservice operation. The time-temperature and microbial contamination level in each cooking step were analyzed. The temperatures of bellflower root, peeled garlic and green onion at receiving were at 13.8$\pm$2.8, 12.6$\pm$2.9 and 13.7$\pm$$0.8^\circC$ respectively, which were above the temperature limit. The time consumed for pre-preparation was up to 90 min at room temperature having high microbial growth potential. The levels of total plate counts (TPC) of bellflower root and garlic were over the limit of $10^6$ CFU/g as were the numbers of coliforms in bellflower roots. There were no microbial reductions in pre-preparation and cooking, which resulted in over $10^5$- $10^6$ CFU/g of TPC at service step. Two CCPs identified were washing/sanitation at pre-preparation and service steps. The control measures were washing/sanitation and temperature control. It was verified that CCPs for no cooking process developed in preceding studies were applicable for the microbiological food safety of this menu item. The HACCP-based standard recipe was developed to produce a quantity for 100 servings by observing the critical limits established for CCPs. These results suggest that the selection of proper provider is imperative to control the microbial contamination of raw materials at purchasing step. Also, the sanitary education program should be developed for the employees to understand and comply the HACCP plan and standard recipe.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.31-38
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• 2016

A novel self-reference sense amplifier with parallel reading during writing operation is proposed. Read access time is improved compared to conventional self-reference scheme with fast operation speed by reducing operation steps to 1 for read operation cycle using parallel reading scheme, while large sense margin competitive to conventional destructive scheme is obtained by using self-reference scheme. The simulation was performed using standard $0.18{\mu}m$ CMOS process. The proposed self-reference sense amplifier improved not only the operation speed of less than 20 ns which is comparable to non-destructive sense amplifier, but also sense margin over 150 mV which is larger than conventional sensing schemes. The proposed scheme is expected to be very helpful for engineers for developing MRAM technology.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.791-795
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• 2006

Urban transit is one of the most effective ways for efficient operation and construction of an urban transit by composition system which is liked originally such as rolling-stock, power, signal and infrastructure. Urban rail transit system is running in domestic, imports major equipments from advanced countries and setup for maintenance. But it takes long time because it does each organizations and lines. Also, signal, power and track system apply different standard by each construction organizations it causes an increasing construction of cost accordingly it desperately needs a systematic countermeasure. Therefore standard specification of urban transit have been establishing and operatingfor efficient operation of urban transit and base technology security that is populace ride to become a base of state economy. After track, power and signal system will be announced. Standard specification become more, the importance of administrationof standards is emphasized more. Specification administrator’s the importance which use a computing support tool recently in railroad part in embossed and is predicted to be more such forward. Therefore we propose the effective method of management with track, power signal system by constructed data-base system.