• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.509-523
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• 1998

A consistent finite element formulation and analytic solutions are presented for stability of thin-walled circular arch. The total potential energy is derived by applying the principle of linearized virtual work and including second order terms of finite semitangential rotations. As a result, the energy functional corresponding to the semitangential moment is newly derived. Analytic solutions for the out-of-plane buckling of symmetric thin-walled curved beam subjected to pure bending or uniform compression with simply supported boundary conditions are obtained. For finite element analysis, the cubic Hermitian polynomials are utilized as shape functions and $16{\times}16$ stiffness matrix for curved beam elements and $14{\times}14$ stiffness matrix for straight beam elements are evaluated, respectively. In order to illustrate the accuracy of this study, analytical and numerical results for lateral buckling problems of circular arch are presented and compared with available analytical solutions.

• Journal of KIISE
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• v.41 no.11
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• pp.958-966
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• 2014

Wireless sensor networks offer a distributed processing environment. Many sensor nodes are deployed in fields that have limited resources such as computing power, network bandwidth, and electric power. The sensor nodes construct their own networks automatically, and the collected data are sent to the sink node. In these traditional wireless sensor networks, network congestion due to packet flooding through the networks shortens the network life time. Clustering or in-network technologies help reduce packet flooding in the networks. Many studies have been focused on saving energy in the sensor nodes because the limited available power leads to an important problem of extending the operation of sensor networks as long as possible. However, we focus on the execution time because clustering and local distributed processing already contribute to saving energy by local decision-making. In this paper, we present a cooperative processing model based on the processing timeline. Our processing model includes validation of the processing, prediction of the total execution time, and determination of the optimal number of processing nodes for distributed processing in wireless sensor networks. The experiments demonstrate the accuracy of the proposed model, and a case study shows that our model can be used for the distributed application.

• Animal cells and systems
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• v.2 no.4
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• pp.477-481
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• 1998

Previous studies have postulated that isometric animals exert similar locomotory capacity (speed, distance) because the amount of energy available for the motion would be the same regardless of body mass (m). To test propriety of this theory, we examined body shape and take-off potential of two frog species, Rana nigromaculata (powerful jumpers) and Bombina orientalis (slow hoppers). Morphological measurements included thigh muscle mass (indicative of total muscle force), hindlimb length (L, determining acceleration distance), and interilial width (shaping take-off motion). To gauge locomotory capacity, take-off speed (v) and take-off angle ($\theta$) were measured from video analyses, and jump distance (R) and take-off Power ($P_{t}$ ) were calculated from equations $R=V^{2}sin2\theta/g$ and ($P_{t}$＝$㎷^{3}/2L$(where g is the gravitational constant). Scaling exponents of morphometric variables for both species were 0.96-1.11 for thigh muscle mass, 0.28-0.29 for hindlimb length, and 0.30-0.36 for interilial width. Scaling exponents of locomotory performance for the two species were -0.01-0.14 for take-off speed, 0.24-0.31 for jump distance, and 0.66-0.84 for take-off power. The results demonstrate that the frogs of this study showed isometric body shape within species, but that take-off response changed allometrically with body mass, indicating that these data did not fully support the previous proposition. An exception was found in take-off speed of B. orientalis, in which the speed changed little with body mass (slope＝-0.01). These findings suggest that the energy availability approach did not properly explain the apparent allometric relations of the take-off response in these animals and that an alternative model such as a power production approach may be worth addressing.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.97-106
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• 2010

Environmental issues resulting from climate change and energy crises have become global issues, and cycling has gained greater popularity for sustainable transportation. Though many cities are trying to build bicycle roads, it is not easy to implement bicycle roads because there is little available space for bicycle facilities. Therefore, road diets have become more popular in Korea. However, there has been no intensive research to date of their impacts. The purpose of this research is to evaluate the effects of road diets and construction of bike lanes. Every benefit, including energy benefit, environmental benefit, and health benefit is considered, while only time savings benefit has been considered in previous studies. The benefit analysis for the Seoul metropolitan area as a case study shows that road diets have a (1) time saving benefit for only five percent of the mode share and (2) enough total benefit even if bicycle mode share is less than two percent.

• Nuclear Engineering and Technology
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• v.40 no.7
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• pp.615-624
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• 2008

In this paper, the contribution of task types and error types involved in the human-related unplanned reactor trip events that have occurred between 1986 and 2006 in Korean nuclear power plants are analysed in order to establish a strategy for reducing the human-related unplanned reactor trips. Classification systems for the task types, error modes, and cognitive functions are developed or adopted from the currently available taxonomies, and the relevant information is extracted from the event reports or judged on the basis of an event description. According to the analyses from this study, the contributions of the task types are as follows: corrective maintenance (25.7%), planned maintenance (22.8%), planned operation (19.8%), periodic preventive maintenance (14.9%), response to a transient (9.9%), and design/manufacturing/installation (6.9%). According to the analysis of the error modes, error modes such as control failure (22.2%), wrong object (18.5%), omission (14.8%), wrong action (11.1 %), and inadequate (8.3%) take up about 75% of the total unplanned trip events. The analysis of the cognitive functions involved in the events indicated that the planning function had the highest contribution (46.7%) to the human actions leading to unplanned reactor trips. This analysis concludes that in order to significantly reduce human-induced or human-related unplanned reactor trips, an aide system (in support of maintenance personnel) for evaluating possible (negative) impacts of planned actions or erroneous actions as well as an appropriate human error prediction technique, should be developed.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.433-440
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• 2014

In this study, a method for the low-carbon active distribution system (ADS) planning is proposed. It takes into account the impacts of both network capacity and demand correlation to the renewable energy accommodation, and incorporates demand response (DR) as an available resource in the ADS planning. The problem is formulated as a mixed integer nonlinear programming model, whereby the optimal allocation of renewable energy sources and the design of DR contract (i.e. payment incentives and default penalties) are determined simultaneously, in order to achieve the minimization of total cost and $CO_2$ emissions subjected to the system constraints. The uncertainties that involved are also considered by using the scenario synthesis method with the improved Taguchi's orthogonal array testing for reducing information redundancy. A novel cuckoo search (CS) is applied for the planning optimization. The case study results confirm the effectiveness and superiority of the proposed method.

• Journal of Pharmacopuncture
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• v.25 no.4
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• pp.382-389
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• 2022

Objectives: The Korean Industrial Standard (KS) for sterile acupuncture needles was established in 2009 based on research on the quality control of acupuncture needles. We aimed to determine the quality of acupuncture needles available in South Korea in 2021 by examining their surface condition and chemical composition using field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). Methods: In South Korea, there are 23 brands of acupuncture needles, and we examined 10-15 needles from each brand, resulting in a total of 285 needles. The microstructures of the needles were assessed by SEM. Using SEM images, we evaluated the acupuncture needle tips for the following defects/aspects: scratches, lumps, detached coating, bent tip, and tip sharpness. EDS was used to determine the chemical composition of the selected acupuncture needles. Results: Overall, 88.4% of 285 needles were found to have at least one type of abnormality. The most frequently observed abnormalities were scratches and dents on the surface (68.1%), followed by detached coating (63.2%), and lumps (61.8%); blunt tips were observed in about 24% of them. Of 252 needles with at least one defect, 86.9% had two or more types of defects. The ratio of the number of needles with any defect to that of needles without any defect varied among brands, ranging from 50% to 100%. Regarding foreign materials, higher proportions of Si and O were observed on the needles, indicating incomplete or detached silicone coating. Conclusion: The quality of acupuncture needles varied among brands, suggesting that further improvements can be made through various inspection methods.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.10
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• pp.1442-1449
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• 2017

Objective: This study investigated the effect of microbial phytase supplementation on growth performance, tibia ash, plasma parameters, apparent ileal digestibility (AID) of amino acid (AA) and apparent digestibility of nutrients in Youxian Sheldrakes fed with low-phosphorus (P) cornsoybean diets. Methods: A total of 350 Youxian Sheldrakes (7d old) were randomly divided into 5 treatment groups: positive control (PC) group has adequate available P diet (0.42% and 0.38%, starter and grower), negative control (NC) group were deficient in available P (0.32% and 0.28%, starter and grower) and NC diet was supplemented with 3 levels of microbial phytase (500, 750, and 1,000 U/kg). Results: Dietary supplementation of phytase in NC diet improved the average daily gain, increased the levels of serum calcium (Ca), tibia Ca and P, AID of AA and apparent digestibility of energy and Ca in starter stage (p<0.05). There was an increased (p<0.001) in the utilization of P from 17.3% to 23.9%. Phytase supplementation (1,000 U/kg) has shown that the AID of His, Thr, Val, indispensable AA, Glu, Pro, and dispensable AA was higher (p<0.05) than that of NC. Moreover, phytase supplementation improved (p<0.05) serum and tibia Ca and P, AID of AA and apparent digestibility of dry matter, crude protein, energy, P and Ca, and reduced (p<0.05) feed to gain ratio (F/G) and the levels of serum alkaline phosphatase in grower stage. Likewise, an increase (p<0.001) in the utilization of P was noticed from 12.6% to 17.2%. Supplement phytase at 750 U/kg improved the AID of His, Thr, Asp, Cys, Pro, and Ser (p<0.05). Conclusion: The microbial phytase supplement could improve growth performance, AID of some AA and apparent utilization of other nutrients in Youxian Sheldrakes, and reduce excreta P load to environment.

• Journal of Korea Foresty Energy
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• v.1 no.2
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• pp.20-27
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• 1981

Populus alba x glandulosa shows greater growth performance in the lower part of the hill than in the upper part. In order to study this reason, correlation between the soil factors and the growth was examined. The results were as follows. 1. Annual mean height growth was 1.29m in foot hill but 0.7m in upper part, showing 184$\%$ better growth in the foot hill than in the upper part and the similar situation was shown in the diameter growth. The longer slope distance, the better growth: generally the good growth shows in the first harf of the distance. 2. High positive correlation shows between the growth performance and soil moisture: r=0.76 in the hight and r=0.71 in the diameter, and also positive correlation between soil depth and the growth performance. r=0.65 in the height and r=0.79 in the diameter. On the other hand, negative correlation between the slope and soil depth are considered as limiting factors to the growth. 3. A significant correlation appeared between growth performance and organic matter and between the growth performance and total nitrogen as well. This shows that the nutrient elements were contained much in the foot hill. 4. The correlation between the height growth and potassium, and between the growth and calcium and pH were shown . 5. However, no correlation was shown between the growth and available phosphate, magnesium and available managanese .

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.316-320
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• 2001

Sixteen growing crossbred Anglo-Nubian goats, 10-12 months old, pre-experimental average body weights of $18.3{\pm}0.28kg$ were randomly allotted to four diets to investigate the efficiency of utilisation of diets containing increasing levels of desiccated coconut waste meal (DCWM) in the tropical environment of Samoa, South Pacific region. The four diets were designated as 1, 2, 3 and 4. Diet 1 that has no DCWM served as the control, while diets 2, 3 and contained different levels of DCWM. Voluntary concentrate intake, growth rate, feed efficiency and nutrient digestibility coefficients were measured. Gross energy (GE) and organic matter (OM) values of the diets increased linearly with increase in the levels of DCWM in the diets. Voluntary concentrate intake decreased with increasing proportion of DCWM in the diets. Forage intake increased with increase in the levels of DCWM diets offered to the growing goats. Total voluntary feed intakes were statistical significant (p<0.05) and the goats on diet 4 had the least intake followed by those on diet 3. Goats an diets 1 and 2 were different in total feed intake but not at a significant level (p>0.05). Feed efficiency (FE) followed the trend of voluntary concentrate intake and daily live weight gains. Dry matter digestibility (DMD) was significantly different (p<0.05) among the goats offered the different diets. DMD improved with increasing levels of DCWM. The goats accepted all, the diets that were compounded with the different levels of dried DCWM and this seems to suggest that DCWM have no deleterious effects. However, the best level at which dried DCWM could replace brewers dried grains in the diets of growing goats is at 38.5% (diet II). Based on voluntary feed intake, live-weight gain and apparent nutrient digestibility coefficients of the goats it could be concluded that DCWM based diets merits further attention as a locally available feed source in ruminants nutrition in the Pacific Island countries where feed availability is seasonal.