• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1004-1009
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• 2004

Precise time synchronization is a main technology in high-speed communications, parallel and distributed processing systems, Internet information industry and electronic commerce. Synchronized clocks are useful for many leasers. Often a distributed system is designed to realize some synchronized behavior, especially in real-time processing in factories, aircraft, space vehicles, and military applications. Nowadays, time synchronization has been compulsory thing as distributed processing and network operations are generalized. A network time server obtains, keeps accurate and precise time by synchronizing its local clock to standard reference time source and distributes time information through standard time synchronization protocol. This paper describes design issues and implementation of a network time server for time synchronization especially based on a clock model. The system uses GPS (Global Positioning System) as a standard reference time source and offers UTC (universal Time coordinated) through NTP (Network Time protocol). Implementation result and performance analysis are also presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.1000-1009
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• 2013

This study investigated changes in behavioral performance before and after watching a multi-view 3D content by using auditory stimuli based on the selective attention theory in order to quantitatively evaluate 3D visual fatigue. Twenty-one undergraduates were asked to report on their current visual and physical condition both in the pre- and post-experiment. A selective attention task was conducted before and after mobile 3D viewing to compare the changes in performance. After performing a Wilcoxon's matched-pairs signed-ranks test on the subjective ratings of 3D visual fatigue, participants were categorized into two groups, unfatigued and fatigued group with a definite criterion. For the unfatigued group, no significant fatigue effects were found in behavioral response times and accuracies to specific auditory targets. In sharply contrast to the unfatigued group, the fatigued group showed significantly delayed response times and less response accuracies. However, no significant changes in accuracies for a working memory task were observed in both groups.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.1002-1009
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• 2009

Precision guidance filter design for a tactical missile with a strapdown seeker aided by low-cost strapdown sensors has been addressed in this paper. The low-cost strapdown sensors consist of an IMU with 3-axis accelerometers and gyroscopes, 3-axis magnetometers, and a barometer. Missile's position, velocity, attitude, and bias error of the barometer are considered as state variables. Since the state and measurement equations are highly nonlinear, we adopt UKF(Unscented Kalman Filter). The proposed guidance filter has a function of a navigation filter if target position error is not considered. In the case that the target position error is introduced, the proposed filter can effectively estimate the relative states of the missile to the true target. For specific engagement scenarios, we can observe that observability problems occur.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.1004-1009
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• 2006

Four male crossbred native beef cattle (average body weight of 427.7 kg) were randomly allocated to four types of cassoy-urea pellet as a source of protein in concentrate according to a $4{\times}4$ Latin square design to determine effect of diets on ruminal fermentation and nutrient digestibility. The four types of cassoy-urea pellets contained cassava hay, soybean meal, urea and binding agent at 79.2:19.8:0:1 (27.9% CP dry matter), 78.4:19.6:1:1 (30.4% CP), 77.6:19.4:2:1 (33.0% CP) and 99:0:0:1 (23.8% CP) for dietary treatments; 1, 2, 3 and 4, respectively. All four concentrate mixtures contained similar crude protein levels (11% CP) and were fed to animals in two equal parts (0.5% of body weight per day) while urea-treated rice straw (5% urea) was given ad libitum. The experiment revealed that dietary concentrate treatments had no effect on dry matter intake while digestibilities of neutral-detergent fiber and crude protein were higher (p<0.05) in cattle fed dietary treatments 1, 2 and 3 than in cattle fed dietary treatment 4. Ruminal ammonia-nitrogen ($NH_3$-N), was higher and acetic acid concentration (C2) and ratio of C2 to propionic acid (C3) were lower (p<0.05) in cattle fed dietary treatments 1, 2 and 3 than in those on treatment 4. It is concluded that use of cassoy-urea pellet as a protein source in concentrates for cattle resulted in improvement of digestibility, ruminal fermentation and rumen ecology. Further research using cassoy-urea pellet in feeding trials with milking cows and fattening beef should be undertaken.

• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.1001-1009
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• 2023

Flow is a concept closely related to intrinsic motivation and is considered a positive factor in sports performance in sports psychology. The purpose of this study was to confirm the addictive nature of Flow through previous studies and propose a new hypothesis that Flow may decrease intrinsic motivation in the long term, unlike previous studies. In line with adaptation level theory and the law of diminishing marginal utility, the satisfaction derived from Flow is continuously decreasing. At some point, the individual's progress is limited and they reach a point where they no longer experience FLOW. However, the individual will continue to try because the desire to experience FLOW again exists. However, failure to experience FLOW and repeated failure will lead to sadness, which will decrease intrinsic motivation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.1001-1009
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• 2012

In this study, the cooling characteristics of combustion gas were investigated by injecting liquid nitrogen ($LN_2$) into a liquid rocket combustion chamber, which uses liquid oxygen (Lox) and kerosene as propellants. $LN_2$ injectors and an extended chamber for mixing were installed at the end of the ordinary LRE combustion chamber, and a nozzle was installed after the chamber for mixing. First, an ignition test of the liquid rocket engine was conducted to verify the stable combustion process. Next, a hot firing test was performed step-by-step for safety. Finally, the test was performed for 20 s. The results showed that the combustion gas of the LRE could be successfully cooled by using $LN_2$.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.7
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• pp.1009-1014
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• 2012

Environmental stress boosts the levels of stress hormones and accelerates energy expenditure which subsequently imbalance the body's homeostasis. L-ascorbic acid (L-AA) has been recognized to mitigate the negative impact of environmental stress on production performances in birds. The present investigation was carried out to elucidate the effect of different dietary levels of L-AA on production performance, egg quality traits and fertility in Japanese quail at low ambient temperature. Sixty matured females (15 wks) were equally divided into three groups (20/group) based on the different dietary levels of L-AA (0, 250 and 500 ppm) and coupled with an equal number of males (1:1) obtained from the same hatch. They were managed in uniform husbandry conditions without restriction of feed and water at 14 h photo-schedule. Except for feed efficiency, body weight change, feed consumption and hen-day egg production were recorded highest in 500 ppm L-AA supplemented groups. Among the all egg quality traits studied, only specific gravity, shell weight and thickness differed significantly (p<0.05) in the present study. Fertility was improved significantly ($p{\leq}0.01$) to a dose dependent manner of L-AA. The findings of the present study concluded that dietary L-AA can be a caring management practice at least in part to alleviate the adverse effect of cold induced stress on production performance in Japanese quail.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1009-1020
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• 2010

In this study, we applied a hierarchial linear model to Anyang city data because students and their schools are hierarchial data structure. As a result, main factors which affect parents' satisfaction to school which their children go to are parents' satisfaction to Anyang city's education policies and areas which their schools located at. We suggest based on the analysis by this hierarchial linear model that if Anyang city make educational policies more efficient and effective in order for students to study in public school without private education and if Anyang city improve environment related with school like those of new cities, parents' satisfaction to school which their children go to will be increased.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1009-1014
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• 2000

In order to detect pantothenic acid (PA), conditions for enzyme-linked immunosorbent assay (ELISA) were established. Anti-PA-BSA antibody was produced from rabbits immunized with PA-bovine serum albumin (BSA) conjugates which were prepared by the bromoacetyl chloride [Bc] method (PA-BSA[Bc]) and by the periodate oxidation [Po] method (PA-BSA[Po]). PA-BSA[Bc] and PA-BSA[Po] was used as a coating antigen for competitive indirect(ci)ELISA. The Anti-PA-BSA[Po] antibody on ciELISA showed no competitive reaction. The detection limit of PA by ciELISA using Anti-PA-BSA[Bc] antibody was 1 ppm. The Anti-PA-BSA[Bc] antibody showed little cross-reactivity to PA derivatives such as pantoyllactone, pantetheine, pantothenyl alcohol, and acetyl CoA. The detection limit of PA by microbiological assay (MBA) was 10 ppb. Assay recoveries of PA in egg, cow's liver, and lettuce by ciELISA were 109, 64, and 344%, respectively, comparing with the MBA results.

• Korean Journal of Head & Neck Oncology
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• v.9 no.2
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• pp.234-243
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• 1993

The thyroid nodules are the most common endocrine disease requiring surgical management. Up to date, various diagnostic techniques and surgical management have been developed. Authors analysed 2285 cases of thyroid nodules who were treated at Department of Surgery, Pusan National University for the duration of 10 years from January 1980 to December 1989 and the results obtained were summerized as follows: 1) Patients were composed of 1727 cases(75.8%) of benign nodule and 558 cases(24.5%) of malignant nodule. Benign nodule was prevalent in forth and fifth decade comparing with malignant nodule was sixth and fifth decade. The sexual distribution revealed female preponderance with 1:10.8 in benign nodule and 1:9.3 in malignant nodule. 2) The histopathologic classfication of benign nodule in decreasing order of frequency were follicular adenoma 1009 cases(54.8%), adenomatous goiter 573 cases(33.3%), simple cyst 65 cases(3.8%), and Hashimoto's thyroiditis 52 cases(3.0%). The malignant disease were papillary adenocarcinoma 460 cases(82.4%), follicular adenocarcinoma 69 cases(12.4%), undifferentiated carcinoma 13 cases (2.0%), and medullary carcinoma 7 cases(1.0%). 3) Fine needle aspiration cytology was performed in 1758 cases and it showed 80.5% of sensitivity, 96.5% of specificity, 19.5% of false negative and 80% of accuracy. 4) The location of nodule was 87.7%, in unilateral, 12.2% in bilateral. 5) On the radioiodine scanning, the incidence of benign nodule with cold nodule was 83.9% and the incidence of benign nodule with hot nodule was 7.5%. The incidence of thyroid carcinoma with cold nodule was 88.3% and the incidence of thyroid carcinoma with hot nodule was 4.6%. 6) Most cases of benign nodules were treated with lobectomy 82.6%, subtotal thyroidectomy 10.1% and subtotal lobectomy 3.0%. Malignant nodules were treated with lobectomy and/or isthmusectomy 37.6%, total thyroidectomy 17.7%, subtotal thyroidectomy 15.4%, and any thyroidectomy and neck dissection 13.5%. 7) Postoperative complications were developed in 3.8% of benign nodules and 13.8% of malignant nodules.