• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.138-142
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• 2018

This study used HILS to test an expansion joint, which is vulnerable to the water hammer effect. The operation data for the HIL simulator was the length rate of the expansion joint by the water hammer, which was used for life prediction based on the vibration durability. For the vibration durability test, the internal pressure of the expansion joint was assumed to be a factor of the durability life, and the lifetime prediction model equation was obtained by curve fitting the lifetime data at each pressure. During the test, the major failure modes of crack and water leakage occurred on the surface of the bellows part. The lifetime prediction model typically follows an inverse power law model. The pressure is a stress factor, and the model is effective in only a specific environment. Therefore, another stress factor such as temperature will be added and considered for a mixed lifetime prediction model in the future.

• Korean Parent-Child Health Journal
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• v.5 no.2
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• pp.224-240
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• 2002

As social changes, there are growing number of instituted infants. Most of them were poor growth and developmental outcome due to situational and environmental vulnerability. Developmental interventions for this infants have been the subjects of debate for many years. The purpose of this study was to evaluate the effectiveness of massage intervention on the physical growth of orphaned infants during the first 6 month of life. This study utilized equivalent control group with repeated measuring by quasi experimental design. Fifty eight orphaned infants were randomly assigned to control(n=28), or an experimental(n=30) group. In addition to routine orphanage care, infants in the experimental group received 15 minutes of massage intervention twice a day, 5 days a week, for 4 weeks. Data has been collected from April 1st, 2000 to August 31st, 2002 and were analyzed using SPSS/PC(Version 10.0) with chi-square test, t-test, and repeated measures ANOVA to determine the effectiveness of massage intervention and to test the homogeneity of general characteristics between experimental and control group. The results were as follows; Compared to the control group, the experimental group has gained significantly more weight(F=33.52, p < .0001) and had larger increases in length(F=10.04, p < .0001) and head circumference(F=49.78, p < .000) after the 4-week intervention period and at 6 months of age. These data demonstrate that massage intervention may be effective in facilitating growth for newborn infants placed in orphanages during first 6 months of life.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.1039-1046
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• 2005

TCP SACK is the unique mechanism to reflect the situation of sink's sequence space, some TCP variants and proposals can perform in conjunction with SACK mechanism for achieving optimal performance. By definition of RFC 2018, however, each contiguous block of data queued at the data receiver is defined in the SACK option by two 32-bit unsigned integers in network byte order. Since TCP Options field has a 40-byte maximum length, when error bursts now, we note that the available option space may not be sufficient to report all blocks present in the receiver's queue and lead to unnecessarily force the TCP sender to retransmit Packets that have actually been received by TCP sink. For overcoming this restriction, in this thesis, a new solution named 'one-byte offset based SACK mechanism' is designed to further improve the performance or TCP SACK and prevent those unwanted retransmissions. The results or both theory analysis and simulation also show that his proposed scheme operates simply and more effectively than the other existing schemes by means of the least bytes and most robust mechanism to the high packet error rates often seen in networks environment.

• Journal of the Korean Society of Costume
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• v.53 no.7
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• pp.139-146
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• 2003

This study was aimed at analyzing a characteristics of the sewing machines and analyzing the effective sewing time in the garment manufacture process, therefore to obtain the basic data concerned with the sewing. operation standardization. The two methods were experimented. First, two garment factories established in Seoul and Geonggi province were randomly selected for the analyzing the sewing speed of the sewing operator for the optimized sewing speed using the equipment of Digital Tachometer HT4100. Second, five garment factories established in Seoul and Geonggi province were randomly selected to analyze the required time data to reach the fixed sewing speed using the lock stitch sewing machine which was used in the sewing factories. The results are divided into 3 categories as follows; 1) Survey results for the optimized sewing speed : The sewing operations of 10~20 cm range were most frequently selected in seam constructions in Korean sewing factories, and the sewing speed of 2,500 R.P.M was most used; 2) Required time to reach the fixed sewing speed using the lock stitch sewing machine : The mean of required time to the fixed sewing speed of 2.500 R.P.M was 3.5 second, and the mean of the real-sewing length during the 3.5 second was 43.8 cm ; 3) Analysis of the optimized sewing speed calculated using these results : The optimized sewing speed for the sewing manufacturers of the upward of 43.8 cm was 2,500 R.P.M. and for the sewing manufacturers of the below of 42.2 cm, the optimized sewing speed was 2.450 R.P.M.

• Journal of Ocean Engineering and Technology
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• v.4 no.2
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• pp.250-250
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• 1990

In this paper, fatigue tests were carried out at stress test levels of 461 MPa, 441 MPa, and 431 MPa by using smooth specimen of$2_{1/4}$ Cr-1 Mo steel with the stress ratio(R) of 0.05. The initiation, growth and coalescense process of the major cracks and sub-cracks among the fatigue cracks on the smooth specimen are investigated and measured under each stress level at a constant cycle ratio by the replica technique with optical microscope. Some of the important results are as follows: In spite of the difference of stress levels, the major crack data gather into a small band in the curve of surface crack length and crack depth against cycle ratio N/Nf. The sub-crack data, however, deviate from the band of the major crack. The growth rates, da/dN, of major and sub-crack plotted against the stress intensity factor range, ${\Delta}K$, have the tendency to be compressed on a relatively small band. But it is more effective to predict fatigue life through major cracks. The propagation behavior of surface microcracks on the smooth specimens coincides with that of the specimen having an artificial small surface defect or through crack.

• The Korean Fashion and Textile Research Journal
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• v.13 no.5
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• pp.759-768
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• 2011

This study is designed to understand current wearing conditions of air force mechanic parkas and evaluate their functionality by examining the wearing conditions and wearers' subjective assessment. By doing so, it also intends to identify issues that require improvements; and to provide basic data for future development of air force mechanic parkas. A survey was conducted as a study methodology, and the collected 1,628 questionnaires were analyzed. Findings of this study are as follows. 1. In the usability assessment, it was found that visibility of body sides was needed to be enhanced since reflective tapes were attached only to the front and back of the body; pockets were too big, but not convenient to keep mechanic tools; the design of hiding hood was not suitable for water-proof clothing; and a new design of size-controllable hood was called for since the hood blocked eye sight. With respect to the fabric, dissatisfaction was identified with durability, cold-proof and fire-proof features. 2. In the mobility assessment, respondents showed low satisfaction with collar heights and neck girths. Mobility score was over moderate level on average, except the parka length that obstructs wearers' movement, and neck and collar size. 3. In the wearability assessment, respondents presented moderate satisfaction with pleasantness, weight, pressure and dampness. However, insulation was found unsatisfactory. Based on the result, this study proposed improvement plans on design, pattern and fabric; and is expected to serve as basic data for developing more effective and functional air force mechanic parkas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.390-399
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• 1988

A conventional BTC has the merit of real time processing and simple computation, but has the problem that its compression rate is low. In this paper, a modified BTC using the Quad Tree which is frequently used in binary image is proposed. The method results in the low compression rate by decreasing the total number of subblocks by mean of making the size of a subblock large in the small variation area of graty level and the size af a subblock small in the large variation area of gary level. For the effective transmission of bit plane, the Huffman run-lengh code for the large size of a subblock and the lookup table for tha small size of a subblock are used. The proposed BTC method show the result of coding 256 level image at the average data rate of about 0.8 bit/pixel.

• Journal of Astronomy and Space Sciences
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• v.32 no.3
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• pp.237-245
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• 2015

A strategy is needed for a regional survey of geosynchronous orbits (GSOs) to monitor known space objects and detect uncataloged space objects. On the basis of the Inter-Agency Debris Committee's recommendation regarding the protected region of geosynchronous Earth orbit (GEO), target satellites with perigee and apogee of $GEO{\pm}200km$ and various inclinations are selected for analysis. The status of the GSO region was analyzed using the satellite distribution based on the orbital characteristics in publicly available two-line element data. Natural perturbation effects cause inactive satellites to drift to two stable longitudinal points. Active satellites usually maintain the designed positions as a result of regular or irregular maneuver operations against their natural drift. To analyze the detection rate of a single optical telescope, 152 out of 412 active satellites and 135 out of 288 inactive satellites in the GSO region were selected on the basis of their visibility at the observation site in Daejeon, Korea. By using various vertical view ranges and various numbers of observations of the GSO region, the detection efficiencies were analyzed for a single night, and the numbers of follow-up observations were determined. The orbital estimation accuracies were also checked using the arc length and number of observed data points to maintain the GSO satellite catalog.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.19 no.2
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• pp.104-109
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• 2016

Purpose: Regurgitation is a common physiological phenomenon in infants. The aim of the present study was to evaluate the efficacy of a new anti-regurgitation (AR) formula (Novalac), thickened with an innovative complex including fibres, on the daily number of regurgitations and to assess its impact on stool consistency and frequency. Methods: Infants younger than five months, presenting at least 5 regurgitations per day were recruited in this trial. The efficacy of the new formula on regurgitation (daily number and Vandenplas score), stool frequency and consistency were assessed at day 14 and 90. Growth data were recorded at each study visit. Results: Ninety babies (mean age $9.6{\pm}5.8weeks$) were included in the full analysis data set. The mean number of regurgitation episodes at inclusion was $7.3{\pm}3.4$. In all infants, regurgitations improved after 2 weeks. The daily number of regurgitations decreased significantly ($-6.3{\pm}3.3$, p<0.001) including in those previously fed a thickened formula ($-6.2{\pm}3.0$, p<0.001). There was no significant change in stool consistency at day 14. After 3 months, 97.5% of infants had formed or soft stools. Growth was appropriate with a slight increase of weight-for-age z-score (from $-0.5{\pm}1.0$ to $-0.1{\pm}0.9$) and no change of weight-for length z-score ($-0.1{\pm}1.1$ to $-0.1{\pm}-1.1$). Conclusion: The new AR formula thickened with an innovative complex is very effective in reducing the daily number of regurgitations without having a negative impact on stools consistency.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.4
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• pp.347-354
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• 2007

This paper describes on the real-time monitoring of net setting and hauling process for fishing operations of Danish seine vessels in the southern waters of Korea as an application of a PC based ECDIS system. Tracking of fishing process was performed for the large scale Danish seine vessel of G/T 90 and 350 PS class using the fishing gear which the length of net, ground rope, head rope and sweep line including warp in both sides were 86m, 104m, 118m and 3,200m, respectively. Tracking information for net setting and hauling process was continuously recorded for 23 fishing operations performed on November and December, 2003. All measurement data, such as trawl position, heading, towing course and past track which was individually time stamped during data acquisition, was processed in real time on the ECDIS and displayed simultaneously on the ENC chart. The results indicated that after the separation of a marker buoy from Danish seiner, the averaged running speed of vessel and the averaged setting period while shooting the seine on the course of diamond shape to surround the fish school in the 23 fishing operations were 8.3 knots and 13.1 minutes, respectively. And with the maker buoy taken on board, the averaged running speed of vessel and the averaged towing period while closing the seine on the straight route was 1.0 knots and 47.0 minutes, respectively. After the closing stage of hand rope, the hand rope was towed by the averaged speed of 2.2 knots during the 13.0 minutes. The average area for route of diamond shape swept by sweep lines of the seine in 23 fishing grounds was $709,951.6m^2$. Further investigation is also planed to provide more quantitative tracking information and to achieve more effective surveillance and control of Danish seine vessels in EEZ fishing grounds.