• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.156-164
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• 2019

In this paper, we propose an efficient dynamic slot re-assignment scheme for swarming drone networks in which networks members merged and split frequently. The leader drone of each network recognizes the slot allocation information of neighbor networks by periodic information exchange among between the drones. Using the information, the leader drone makes a decision how to reallocate the slots between members in case of network merge. The non-competitive method in the proposed scheme can re-assign the slots without any slot collision and shows always superior performance than competitive scheme. The competitive method in the proposed scheme reduces the number of slots that should be re-assigned in case of network merge. The experimental performance analysis shows that the proposed scheme performs better or at least equal to the performance of the competitive scheme in a swarming drone network.

• Journal of Gastric Cancer
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• v.22 no.1
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• pp.35-46
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• 2022

Background: The correlation between hospital volume and postoperative outcomes has led to the centralization of complex procedures in several countries. However, the results reported in relation to gastric cancer (GC) are contradictory. This study aimed to analyze GC surgical volumes and 30-day postoperative mortality in Italy and to provide a simulation for modeling centralization of GC resections based on district case volumes. Methods: A national registry was used to identify all GC resections, record mortality rates, and track the national in-border GC resection health travel. Hospitals were grouped according to caseload. Centralization of all GC procedures performed within the same district was modeled. The outcome measures were a minimal volume of 25 GC resections/year and the 30-day postoperative mortality. Results: In 2018, 5,873 GC resections were performed in 498 Italian hospitals (mean resections per hospital per year: 11.8); the postoperative mortality rate (5.51%) was tracked from 2016-2018. GC resection health travel ranged from 2% to 50.5%, with a significant (P<0.001) difference between northern and central/southern Italy. The mean mortality rate was 7.7% in hospitals performing one to 3 GC resections per year, compared with 4.7% in those with >17 GC resections/year (P≤0.01). Most Italian districts achieved 25 procedures/year after centralization; however, 66.3% of GC cases in southern Italy vs. 42.2% in central and 52.7% in the northern regions (P<0.001) required reallocation. Conclusion: Postoperative mortality after GC resection correlated with hospital volume. Despite health travel, most Italian districts can reach a high-volume threshold, but discrepancies in mortality rates are alarming.Trial RegistrationResearch Registry Identifierresearchregistry6869

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.1-11
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• 2010

K company produces semiconductor package products under the make-to-order policy to supply for domestic and foreign semiconductor manufacturing companies. Its production process is a machine-paced assembly line type, which consists of die sawing, assembly, and test. This paper suggests three plans to increase process throughput based on the process analysis of K company and evaluates them via a simulation model using a real data collected. The three plans are line balancing by adding machines to the bottleneck process, product group scheduling, and reallocation of the operators in non-bottleneck processes. The evaluation result shows the highest daily throughput increase of 17.3% with an effect of 2.8% reduction of due date violation when the three plans are applied together. Payback period for the mixed application of the three plans is obtained as 1.37 years.

• The Plant Pathology Journal
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• v.40 no.1
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• pp.30-39
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• 2024

The conservation of the endangered Korean fir, Abies koreana, is of critical ecological importance. In our previous study, a yeast-like fungus identified as Aureobasidium pullulans AK10, was isolated and shown to enhance drought tolerance in A. koreana seedlings. In this study, the effectiveness of Au. pullulans AK10 treatment in enhancing drought tolerance in A. koreana was confirmed. Furthermore, using transcriptome analysis, we compared A. koreana seedlings treated with Au. pullulans AK10 to untreated controls under drought conditions to elucidate the molecular responses involved in increased drought tolerance. Our findings revealed a predominance of downregulated genes in the treated seedlings, suggesting a strategic reallocation of resources to enhance stress defense. Further exploration of enriched Kyoto Encyclopedia of Genes and Genomes pathways and protein-protein interaction networks revealed significant alterations in functional systems known to fortify drought tolerance, including the terpenoid backbone biosynthesis, calcium signaling pathway, pyruvate metabolism, brassinosteroid biosynthesis, and, crucially, flavonoid biosynthesis, renowned for enhancing plant drought resistance. These findings deepen our comprehension of how AK10 biostimulation enhances the resilience of A. koreana to drought stress, marking a substantial advancement in the effort to conserve this endangered tree species through environmentally sustainable treatment.

• The Korean Journal of Air & Space Law and Policy
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• v.27 no.1
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• pp.123-156
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• 2012

This study focuses on the satellite licenses and the requirements for satellite spectrum management (i.e. frequency allocation) in Korean satellite industry via comparative analyses against those cases in other developed countries, in order to provide complementary measures to the domestic satellite policies. The satellite industry is one of the main pursuits of a nation's efforts, and it shows distinct characteristics depending on various factors such as national defense and security. In addition, the industry is determined by the nation's market size as well as its international relationship. Consequently, the present study considers examples from various organizations and nations - including U.S.A, Japan, and ITU - and provides a hybrid policy that is well customized for the domestic market. This study looks at similarities between policies of other countries, and finds any supplements for domestic polices by specifying similar cases in others and analyzing their results. The main purpose of this study, therefore, is to find the best agreement for domestic policy with internal interpretation, rather accepting others. While the licensing method for domestic satellites need not be distinct from that of other nations, the case of using non-Korean licensed satellites must be complemented by the conditions in the domestic market. Furthermore, the spectrum management is essential to the nation's satellite industry since the spectrum is a scarce resource. As such, spectrum management that is carefully designed to incorporate the rapidly changing international market demand is crucial to provide a sufficient supply for domestic space industry. In the present study, we find that auction-like market based approaches together with measures to avoid exclusive uses of the scarce resource (e.g. share, leas and reallocation) would provide an excellent method for the domestic satellite industry.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.11
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• pp.256-264
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• 2020

Industrial Wireless Sensor Networks (IWSNs) is exploited to achieve various objectives such as improving productivity and reducing cost in the diversity of industrial application, and it has requirements such as low-delay and high reliability packet transmission. To accomplish the requirement, the network manager performs graph construction and resource allocation about network topology, and determines the transmission cycle and path of each node in advance. However, this network management scheme cannot treat mobile devices that cause continuous topology changes because graph reconstruction and resource reallocation should be performed as network topology changes. That is, despite the growing need of mobile devices in many industries, existing scheme cannot adequately respond to path failure caused by movement of mobile device and packet loss in the process of path recovery. To solve this problem, a network management scheme is required to prevent packet loss caused by mobile devices. Thus, we analyse the location and movement cycle of mobile devices over time using machine learning for predicting the mobility pattern. In the proposed scheme, the network manager could prevent the problems caused by mobile devices through performing graph construction and resource allocation for the predicted network topology based on the movement pattern. Performance evaluation results show a prediction rate of about 86% compared with actual movement pattern, and a higher packet delivery ratio and a lower resource share compared to existing scheme.

• Korean Journal of Occupational Health Nursing
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• v.7 no.1
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• pp.83-96
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• 1998

The study was conducted to analyze employees' and employers' awareness of occupational health programs for the purpose of evaluating the effectiveness of the program employed in small-scale enterprises (SSE). The 400 SSE that have under 50 employees and have been supported by the Government were selected for mail survey, and 120 employers and 318 employees of 183 factories returned the questionnaires. The results are as follows; 1) 33.8% of employees were not aware of the fact that their factories have been supported by Government, and 69.1% of employees did not know who was the monitor of that program. Only 147% of employees and 35.5% of employers agreed that the supported program reflected their opinions well. 2) 45.1% of employees participated in health education classes more than once. But only 15.6% of them considered the classes as very helpful. 21.1% of employers were much aware of health education schedule, and 44.2% reported that it was helpful for the prevention of occupational diseases. 3) 68.8% of employers were aware of the possibility of occupational diseases that could occur in their factories. And 36.5% of employers reported that some criteria were used for job reallocation to their employees. But only 9.7% of employees were assigned new job based on the result of health status examination. 4) 65.6% of employees were aware of the periodic evaluation for work environment, and 43.3% knew the evaluation results. Among participated SSE, 5.9% have a planning department for improving work environment, and 46.2% actually carried out the program for improving work environment. The findings showed that the employers and employees of SSE had insufficient knowledge of the occupational health program that have been employed in their workplace. It is essential to lead more active participation of employers and employees in their occupational health programs so as that the programs are to improve their health status as well as work environment more effectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.437-442
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• 2015

Recently, the size of point cloud is increasing rapidly with the high advancement of 3D terrestrial laser scanners. The study aimed for improving a file-referring octree, introduced in the preceding study, which had been intended to generate an octree and to query points from a large point cloud, gathered by 3D terrestrial laser scanners. To the end, every leaf node of the octree was designed to store only one file-pointer of its first point. Also, the point cloud file was re-constructed to store points sequentially, which belongs to a same leaf node. An octree was generated from a point cloud, composed of about 300 million points, while time was measured during querying proximate points within a given distance with series of points. Consequently, the present method performed better than the preceding one from every aspect of generating, storing and restoring octree, so as querying points and memorizing usage. In fact, the query speed increased by 2 times, and the memory efficiency by 4 times. Therefore, this method has explicitly improved from the preceding one. It also can be concluded in that an octree can be generated, as points can be queried from a huge point cloud, of which larger than the main memory.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.242-250
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• 2016

This study was conducted to investigate whether Stroop-related cognitive task will be affected according to the preceding affective valence factored by matchedness in response time(RT) and whether facial recognition will be indexed by specific event-related potentials(ERPs) signature in normal person as in patients suffering from affective disorder. ERPs primed by subliminal(30ms) facial stimuli were recorded when presented with four pairs of affect(positive or negative) and cognitive task(matched or mismatched) to get ERP effects(N2 and P300) in terms of its amplitude and peak latency variations. Behavioral response analysis based on RTs confirmed that subliminal affective stimuli primed the target processing in all affective condition except for the neutral stimulus. Additional results for the ERPs performed in the negative affect with mismatched condition reached significance of emotional-face specificity named N2 showing more amplitude and delayed peak latency compared to the positive counterpart. Furthermore the condition shows more positive amplitude and earlier peak latency of P300 effect denoting cognitive closure than the corresponding positive affect condition. These results are suggested to reflect that negative affect stimulus in subliminal level is automatically inhibited such that this effect had influence on accelerating detection of the affect and facilitating response allowing adequate reallocation of attentional resources. The functional and cognitive significance with these findings was implied in terms of subliminal effect and affect-related recognition modulating the cognitive tasks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1072-1078
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• 2008

In this paper, we propose an efficient superposition coding multiplexing(SCM) method based on power allocation in descending order for fading broadcast channels in which per-user minimum and maximum rate constraints are considered in order to maximize the transmission effectiveness. It consists of three steps as follows. In the first step, a user group is selected to maximize the number of users with whom a transmitter can communicate instantaneously. In the second step, per-user power allocation for each user is done in descending order of transmit power by determining a maximum allowable interference power from all subsequent interfering users in order to guarantee its corresponding minimum rate, and then a residual power is calculated. The final step is performed if some power remains even after the second step. In this step, additional power allocation is performed up to the maximum transmit power to provide the maximum rate to the corresponding user, again in ascending order, starting from the last user in descending order. But, this method does not require power reallocation to subsequent users because tentative power allocation in the second step has been performed in descending order to guarantee the minimum rate for each user, taking into account the maximum allowable interference power from all the subsequent users. Therefore, the proposed method gets more efficient in term of computational complexity when per-user minimum as well as maximum rate constraints exist, especially as the number of users increases.