• Journal of the Korea Society for Simulation
• /
• v.21 no.4
• /
• pp.25-33
• /
• 2012

Armed helicopter is an integral part of armed forces, which conducts vital missions, such as anti-armor attack, close air support, escorting air assault operations, and reconnaissance. A typical cockpit arrangement of armed helicopters has been a tandem configuration. This is to reduce the frontal area, which in turn increases the forward speed as well as reduces the chance of being hit by enemy fires. However, many armed helicopters in the world are now being developed as a side-by-side configuration. Such configuration is quite different from the conventional cockpit arrangement in light of the crew communications and situational awareness. Therefore, the main objective of this study is to find the optimized combination of mission tasks among pilots in a side-by-side configuration cockpit by measuring the workload using the NASA Task Load Index method. The experimental results indicate that the workload of crew members differ as disparate tasks are being performed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.32 no.3
• /
• pp.59-70
• /
• 2009

This study is the result of meta evaluation for the self evaluation of defense R&D programs in Korea by using meta evaluating indicators. The overall meta evaluation result of defense R&D programs gained 74.3 points out of 100, so it was evaluated as 'Good'. But it demonstrated that further improvement for overall system of defense R&D programs evaluation is required. And especially, it demonstrated that more alternatives are necessary in order to improve the utilizations and the feedbacks of evaluation results. The evaluation context component gained 80.2 points out of 100, so it was evaluated as 'Very Good'. The evaluation input component gained 73.1 points out of 100, so it was evaluated as 'Good'. The evaluation process component gained 74.8 points out of 100, so it was evaluated as 'Good'. And the evaluation outcome component gained 69.0 points out of 100, so it was evaluated as 'Good'. Basic model of meta evaluation was derived from the literature review and brain storming. And this meta evaluation model was determined by adopting the result of experts who performed evaluations for defense R&D programs in recent years. The reliability of components and items was verified by Cronbach's a coefficient. It was over 0.6 in evaluation components and items. And the reliability of evaluation context was 0.877, that of evaluation input was 0.755, that of evaluation process was 0.755, that of evaluation output was 0.755 respectively. From the analysis, it is attempted to identify possible problems and to find out the ways of improvements related to the self evaluation system of defense R&D programs. The ultimate objective of this study is to manage the programs effectively and improve the reliability and the objectiveness of the defense R&D programs.

• Journal of Korean Society on Water Environment
• /
• v.23 no.5
• /
• pp.591-599
• /
• 2007

The quality of water released from a stratified reservoir is dependent on various factors such as the location and shape of intake facility, structure of reservoir stratification, profile of water quality constituent, and withdrawal flux. Sometimes, selective withdrawal capabilities can provide the operational flexibility to meet the water quality demands both in-reservoir and downstream. The objective of this study was to evaluate the performance of a one-dimensional reservoir selective withdrawal model (SELECT) as a tool for supporting downstream water quality management for Daecheong and Imha reservoirs. The simulated water quality variables including water temperature, dissolved oxygen (DO), conductivity, turbidity were compared with the field data measured in tailwater. The model showed fairly satisfactory results and high reliability in simulating observations. The coefficients of determinant between simulated and observed turbidity values were 0.93 and 0.95 for Daecheong and Imha reservoirs, respectively. The outflow water quality was significantly influenced by water intake level under fully stratified condition, while the effect of intake amount was minor. In conclusion, the SELECT is simple but effective tool for supporting downstream water quality prediction and management for both reservoirs.

• Journal of Korea Water Resources Association
• /
• v.34 no.6
• /
• pp.701-711
• /
• 2001

Forecasting of water quality variation is not an easy process due to the complicated nature of various water quality factors and their interrelationships. The objective of this study is to test the applicability of neural network models to the forecasting of the water quality at Gongju station in Geum River. This is done by forecasting monthly water qualities such as DO, BOD, and TN, and comparing with those obtained by ARIMA model. The neural network models of this study use BP(Back Propagation) algorithm for training. In order to improve the performance of the training, the models are tested in three different styles ; MANN model which uses the Moment-Adaptive learning rate method, LMNN model which uses the Levenberg-Marquardt method, and MNN model which separates the hidden layers for judgement factors from the hidden layers for water quality data. the results show that the forecasted water qualities are reasonably close to the observed data. And the MNN model shows the best results among the three models tested

• International Journal of Industrial Entomology and Biomaterials
• /
• v.17 no.2
• /
• pp.165-168
• /
• 2008

The hybrid ($CSR2{\times}CSR4$) eggs treated with acid were taken up for the study with an objective to develop long-term preservation schedule. The hybrid eggs obtained with two mating duration (3 h and 6 h) and oviposition period (6 h and 24 h) with two age groups of eggs (24 h and 36 h) were treated with Hydrochloric acid. These eggs were subjected to preservation at $5^{\circ}C$ in single step refrigeration and at $5^{\circ}C$ and $2.5^{\circ}C$ under double step refrigeration from $10{\sim}120$ days. These eggs were released from the cold storage as per the specified durations and incubated at standard conditions and allowed 2 h for hatching at 450 lux light. Hatchability was found to be significantly higher or on par with the control in three treatments (T1, T2 and T4) where the eggs are preserved continuously at $5^{\circ}C$ up to 30 days. However under double step refrigeration, hatching was not significantly affected in 20+60 day's combination of T1 treatment up to 80 days. Bioassay studies of the promising treatment i.e.. T1 with (20+60) days indicated that early stage loss and cocoon yield was found to be on par with the control. Hence this treatment was recommended for preservation of acid treated new bivoltine hybrid layings. Details of the hatchability and rearing performance of long term preservation of acid treated eggs are discussed.

• The Journal of the Korea Contents Association
• /
• v.15 no.1
• /
• pp.451-461
• /
• 2015

The objective of this research is investigating the mediating effect of job engagement on the relationship between job autonomy and innovative behavior in public organizations. Major findings from Structural Equation Model analysis demonstrates that the variable 'job engagement' took a positive role between job autonomy and innovative behavior. From theoretical point, this result provides the empirical evidence of causal relationship in the three components of attitude-cognition, emotion, and action, which contributes to the advancement of action theory. Some policy implications can be drawn from the empirical findings. Firstly, job autonomy need to be seriously considered as a strategic instrument for the encouragement of innovative behavior. Secondly, job engagement of employees need to be more carefully monitored to stimulate the innovative behavior in the public organizations. In public organizations, enhancement of innovative behavior can not be achieved from institutional arrangements. Provision of job autonomy is more effective method of behavior change than performance management approach.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.4
• /
• pp.403-411
• /
• 2020

This paper discusses the main findings of the development of the twin-hull Car ferry for island freight and passenger transport. The final model had a 19 m wide beam to create enough space for cars on the deck area and thus, enhance the economic feasibility in the market. The vessel had a V-shape with a bulbous bow to minimize the wave-making resistance and the hydrodynamic performance of the ship was verified through computational fluid dynamics. Multi-objective optimization problems of Pareto simulated annealing were used to achieve a weight reduction of approximately 3.9 % and reduce the manufacturing cost. The main results obtained in this study are expected to be useful to engineers and professionals in related industries interested in research on twin catamaran.

• Journal of Korean Neurosurgical Society
• /
• v.50 no.3
• /
• pp.179-184
• /
• 2011

Objective : The aim of this study is to evaluate the therapeutic effects of gamma knife radiosurgery (GKRS) in patients with multiple brain metastases and to investigate prognostic factors related to treatment outcome. Methods : We retrospectively reviewed clinico-radiological and dosimetric data of 36 patients with 4-14 brain metastases who underwent GKRS for 264 lesions between August 2008 and April 2011. The most common primary tumor site was the lung (n=22), followed by breast (n=7). At GKRS, the median Karnofsky performance scale score was 90 and the mean tumor volume was 1.2 cc (0.002-12.6). The mean prescription dose of 17.8 Gy was delivered to the mean 61.1% isodose line. Among 264 metastases, 175 lesions were assessed for treatment response by at least one imaging follow-up. Results : The overall median survival after GKRS was $9.1{\pm}1.7$ months. Among various factors, primary tumor control was a significant prognostic factor ($11.1{\pm}$1.3 months vs. $3.3{\pm}2.4$ months, p=0.031). The calculated local tumor control rate at 6 and 9 months after GKRS were 87.9% and 84.2%, respectively. Paddick's conformity index (>0.75) was significantly related to local tumor control. The actuarial peritumoral edema reduction rate was 22.4% at 6 months. Conclusion : According to our results, GKRS can provide beneficial effect for the patients with multiple (4 or more) brain metastases, when systemic cancer is controlled. And, careful dosimetry is essential for local tumor control. Therefore, GKRS can be considered as one of the treatment modalities for multiple brain metastase.

• Journal of Korean Neurosurgical Society
• /
• v.50 no.3
• /
• pp.191-194
• /
• 2011

Objective : The aim of this study was to analyze the treatment outcome of patients with vein of Galen aneurysmal malformations (VGM). Methods : Clinical and angiographic data of six consecutive patients with VGM were retrospectively reviewed. VGMs were angiographically classified by Yasargil's method. Treatment outcomes were evaluated. Results : Mean age at initial treatment was $4.4{\pm}5.7$ months. Angiographic types of VGMs were type II in two patients and type III in four. Three patients had cardiac symptoms and the others were asymptomatic. Two patients were treated with transvenous embolization, three with transarterial embolization, and one was managed conservatively. Two patients died due to venous hypertension few days after transvenous approach. Of three patients who were transarterially embolized, one was completely occluded with Onyx and two were incompletely occluded. During the follow-up period (range, one to six years) two of three patients treated with transarterial approach were asymptomatic and the other showed mild symptoms. One patient who was managed conservatively showed normal performance. Conclusion : Transarterial embolization of VGMs may be better than transvenous approach in terms of the treatment outcome and complication. Further studies are needed because of the rarity of the disease and rapid advancement of endovascular techniques.

• Journal of the military operations research society of Korea
• /
• v.36 no.2
• /
• pp.53-69
• /
• 2010

The long-term purpose of Military Acquisition Program Management (MAPM) is to fulfill requested performance, budget, and timing of military capability building. The Defense Acquisition Program Administration was established in 2006 and it adopted Integrated Control System. Moreover, there have no much studies done to examine the condition of Defense Capability Improvement Project in Korea through an empirical research although there are sixty one organizations are operating currently under Defense Capability Improvement Project. The objective of this study is to recognize Military Acquisition Program Management as a single project and to critically review relationship between Critical Success Factors (CSF) and Military Acquisition Program Management. Accordingly, three determinants to lead to successful Military Acquisition Program Management are "Communication" "User Participation" and "User Requirement." This study also demonstrates that Critical Success Factors have distinctive influences on successful Military Acquisition Program Management based on characteristic, size and phase of project. In retrospect, it is meaningful that Integrated Project Team (IPT) could classify priority of management according to characteristic, size and phase of project in the course of implementation.