• Information Systems Review
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• v.11 no.2
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• pp.131-145
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• 2009

Knowledge management is systematic management of vital knowledge resources and its associated processes of creating, gathering, organizing, diffusion, use and exploitation. A key challenge emerging for such organizations is how to encourage knowledge sharing within organization because knowledge is the organization's intellectual capital, of increasing importance in promoting competitive advantages. Isolated initiatives for promoting knowledge sharing and team collaboration, without taking consideration of the knowledge sharing limitations and constraints can defeat further development of KM culture. This article investigates knowledge sharing bottlenecks and proposes the use of community of practice as an effective instrument for knowledge sharing. The article demonstrates the opportunity for overcoming barriers of knowledge sharing through the application of communities of practice. The article introduces a steel company case as the best practice of communities of practice. Then, the paper empirically analyzes the case study to provide evidence for the feasibility and effectiveness of the proposed approach.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.1
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• pp.31-38
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• 2012

Next generation cellular applications and smart phone usage generate very heavy wireless data traffic. It becomes ineluctable for mobile network operators to have multiple core network entities such as Serving Gateway and Packet Data Network Gateway in 4G-LTE to share this high traffic generated. A typical configuration consists of multiple serving gateways behind a load-balancer which would determine which serving gateway would service a end-users'request. Such hardware is expensive, has a rigid policy set, and is a single point of failure. Another perspective of today's increasingly high data traffic is that besides it is being widely accepted that the high bandwidth L TE provides is creating bottlenecks for service providers by the increasing user bandwidth demands without creating any corresponding revenue improvements, a hidden problem that is also passively advancing on the newly emerging 4G-LTE that may need more immediate attention is the network signaling traffic, also known as the control-plane traffic that is generated by the applications developed for smartphones and tablets. With this as starting point, in this paper, we propose a solution, by a new approach considering OpenFlow switch connected to a controller, which gains flexibility in policy, costs less, and has the potential to be more robust to failure with future generations of switches. This also solves the problem of scaling the control-plane traffic that is imperative to preserve revenue and ensure customer satisfaction. Thus, with the proposed architecture with OpenFlow, mobile network operators could manipulate the traffic generated by the control-plane signaling separated from the data-plane, besides also reducing the cost in installing multiple core-network entities.

• Advances in Energy Research
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• v.2 no.1
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• pp.1-9
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• 2014

The green microalgae Chlamydomonas reinhardtti is well-known specie in the terms of $H_2$ production by photo fermentation and has been studying for a long time. Although the $H_2$ production yield is promising; there are some bottlenecks to enhance the yield and efficiency to focus on a well-designed, sustainable production and also scaling up for further studies. D1 protein of photosystem II (PSII) plays an important role in photosystem damage repair and related to $H_2$ production. Because Chlamydomonas is the model algae and the genetic basis is well-studied; metabolic engineering tools are intended to use for enhanced production. Mutations are focused on D1 protein which aims long-lasting hydrogen production by blocking the PSII repair system thus $O_2$ sensitive hydrogenases catalysis hydrogen production for a longer period of time under anaerobic and sulfur deprived conditions. Chlamydomonas CC124 as control strain and D1 mutant strains(D240, D239-40 and D240-41)are cultured photomixotrophically at $80{\mu}mol\;photons\;m^{-2}s^{-1}$, by two sides. Cells are grown in TAP medium as aerobic stage for culture growth; in logarithmic phase cells are transferred from aerobic to an anaerobic and sulfur deprived TAP- S medium and 12 mg/L initial chlorophyll content for $H_2$ production which is monitored by the water columns and later detected by Gas Chromatography. Total produced hydrogen was $82{\pm}10$, $180{\pm}20$, $196{\pm}20$, $290{\pm}30mL$ for CC124, D240, D239-40, D240-41, respectively. $H_2$ production rates for mutant strains was $1.3{\pm}0.5mL/L.h$ meanwhile CC124 showed 2-3 fold lower rate as $0.57{\pm}0.2mL/L.h$. Hydrogen production period was $5{\pm}2days$ for CC124 and mutants showed a longer production time for $9{\pm}2days$. It is seen from the results that $H_2$ productions for mutant strains have a significant effect in terms of productivity, yield and production time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.130-139
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• 2016

The purpose of this paper is to analyze the problems and the sources of defective products and draw improvement plans in a small plastic boat manufacturing process using TOC (Theory Of Constraints) and statistical analysis. TOC is a methodology to present a scheme for optimization of production process by finding the CCR (Capacity Constraints Resource) in the organization or the all production process through the concentration improvement activity. In this paper, we found and reformed constraints and bottlenecks in plastic boat manufacturing process in the target company for less defect ratio and production cost by applying DBR (Drum, Buffer, Rope) scheduling. And we set the threshold values for the critical process variables using statistical analysis. The result can be summarized as follows. First, CCRs in inventory control, material mix, and oven setting were found and solutions were suggested by applying DBR method. Second, the logical thinking process was utilized to find core conflict factors and draw solutions. Third, to specify the solution plan, experiment data were statistically analyzed. Data were collected from the daily journal addressing the details of 96 products such as temperature, humidity, duration and temperature of heating process, rotation speed, duration time of cooling, and the temperature of removal process. Basic statistics and logistic regression analysis were conducted with the defection as the dependent variable. Finally, critical values for major processes were proposed based on the analysis. This paper has a practical importance in contribution to the quality level of the target company through theoretical approach, TOC, and statistical analysis. However, limited number of data might depreciate the significance of the analysis and therefore it will be interesting further research direction to specify the significant manufacturing conditions across different products and processes.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.8
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• pp.1063-1072
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• 2012

Effective population size ($N_e$) is an important measure to understand population structure and genetic variability in animal species. The objective of this study was to estimate $N_e$ in Sapsaree dogs using the information of rate of inbreeding and genomic data that were obtained from pedigree and the Illumina CanineSNP20 (20K) and CanineHD (170K) beadchips, respectively. Three SNP panels, i.e. Sap134 (20K), Sap60 (170K), and Sap183 (the combined panel from the 20K and 170K), were used to genotype 134, 60, and 183 animal samples, respectively. The $N_e$ estimates based on inbreeding rate ranged from 16 to 51 about five to 13 generations ago. With the use of SNP genotypes, two methods were applied for $N_e$ estimation, i.e. pair-wise $r^2$ values using a simple expectation of distance and $r^2$ values under a non-linear regression with respective distances assuming a finite population size. The average pair-wise $N_e$ estimates across generations using the pairs of SNPs that were located within 5 Mb in the Sap134, Sap60, and Sap183 panels, were 1,486, 1,025 and 1,293, respectively. Under the non-linear regression method, the average $N_e$ estimates were 1,601, 528, and 1,129 for the respective panels. Also, the point estimates of past $N_e$ at 5, 20, and 50 generations ago ranged between 64 to 75, 245 to 286, and 573 to 646, respectively, indicating a significant $N_e$ reduction in the last several generations. These results suggest a strong necessity for minimizing inbreeding through the application of genomic selection or other breeding strategies to increase $N_e$, so as to maintain genetic variation and to avoid future bottlenecks in the Sapsaree population.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.415-420
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• 2020

Crowd flows occur in metropolitan railway transit stations, terminals, multiple buildings, and stadiums and are important in ensuring the safety as well as smooth flow of pedestrians in these facilities. In this study, the author developed a new computational analysis method for crowd flow dynamics and applied it to models of transit connecting paths. Using the analysis method, the potential value of the exit was assigned the smallest value, and the potential value of the surrounding grids gradually increased to form the overall potential map. A pathline map was then constructed by determining the direction vector from the grid with large potential value to the grid and small potential. These pathlines indicate basic routes of passenger flow. In all models of the analysis object, the pedestrians did not move to the first predicted shortest path but instead moved using alternative paths that changed depending on the situation. Even in bottlenecks in which pedestrians in both directions encountered each other, walking became much smoother if the entry time difference was dispersed. The results of the analysis show that a method for reducing congestion could be developed through software analysis such as passenger flow analysis without requiring hardware improvement work at the railway station.

• Journal of Korea Multimedia Society
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• v.19 no.7
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• pp.1166-1178
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• 2016

In Internet of Things (IoT) environments, billions of interconnected devices and multimedia sensors generate a huge amount of multimedia traffic. Since the environment are in general deployed as a server-centric architecture wireless sensor networks could be bottlenecks between IoT gateways and IoT devices. The bottleneck causes high power consumption of the device and triggers very heavy network overload by transmission of sensing data. The deterioration could decrease the quality of multimedia streaming service due to delay, loss, and waste of device power. Thus, in this paper, we propose a context-based adaptive multimedia streaming scheme to support enhanced QoS and low power consumption in IoT environments. The goal of the scheme is to increase quality score per voltage of the streaming service, given an adaptation algorithm with context that are classified network and hardware such as throughput, RTT, and CPU usage. From the both context, the quality score per voltage is used in the comparison of a only network context-based adaptive multimedia streaming scheme, a fixed multimedia streaming and our scheme. As a result, we achieves a high improvement that means the quality score per voltage is increased up to about 4, especially in case of resolution change.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.9
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• pp.1042-1054
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• 1999

공유메모리 병렬프로그램의 오류수정에서 경합의 탐지는 중요하다. 왜냐하면 경합은 잘못된 수행 결과를 초래할 뿐만 아니라, 의도하지 않은 프로그램의 비결정적인 수행을 유발하여 오류수정을 어렵게 하기 때문이다. 특히 최초경합의 탐지는 더욱 중요하다. 그 이유는 최초경합을 제거함으로써 나머지 경합들을 방지할 수도 있기 때문이다. 기존의 수행중 경합 탐지기법들은 접근별 보고방식을 기반으로 하는데, 이 기법들은 임의 공유변수에 대한 병행 쓰레드들의 모든 접근사건들을 검사하기 위해서 접근역사라는 유일한 공유정보를 이용하므로 탐지과정에 심각한 병목현상을 유발시킨다. 그러나, 최초경합 탐지를 위한 경우 이러한 병목현상은 크게 개선될 수 있다. 본 논문에서는, 각 접근사건 검사를 위해 각 쓰레드에 공유되지 않는 독립적인 접근역사를 별개로 두고, 경합을 보고하는 시점인 쓰레드 합류시점에서만 공유되는 접근역사를 이용하도록 함으로써 병목현상을 개선하여 최초경합을 탐지할 수 있는 새로운 수행중 탐지기법을 제안한다. 그러므로 본 기법은 최초경합을 보다 효율적으로 탐지할 수 있기 때문에 수행중 경합 탐지를 더욱 효율적이고 실용적으로 할 수 있다. Abstract Detecting races is important for debugging shared-memory parallel programs, because the races lead to unintended nondeterministic executions of the programs as well as erroneous result and then make debugging programs difficult. Especially, detecting the first races is more important. The reason is that the removal of the first races can make other races disappear. Most existing on-the-fly techniques to detect the races are based on per- access reporting method incurring the serious central bottleneck, because the techniques use unique shared information called access history for checking all accesses of concurrent threads to a shared variable. Such bottleneck, however, can be improved considerably in case of detecting first races. This paper presents a new on-the-fly technique which detects the first races with reduced bottleneck through checking each accesses with private access histories and finally reporting races with shared access histories. Therefore, this technique makes on-the-fly race detection more efficient and practical.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4C
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• pp.349-354
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• 2009

In this paper, a new motion compensation scheme to reduce external memory access frequency which is one of the major bottlenecks for real-time decoding is proposed. Most H.264/AVC decoders store reference pictures in external memories due to the large size and reference blocks are read into the decoder core as needed during decoding. If the reference data access is done for each reference block in decoding sequence, the memory bandwidth can be unacceptable for real-time decoding. This paper presents a memory access scheme for motion compensation to read as many reference data as possible with reduced memory access frequency by analyzing reference data access pattern for each macroblock. Experimental results show that the proposed motion compensation scheme leads to approximately 30% improvement in memory bandwidth requirement.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.6
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• pp.637-647
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• 2010

Recent embedded systems are being more complicated due to their hierarchical software architecture including operating systems. The performance of such complicated software architecture could not be well analyzed through separate analysis of each software layer; the combined effect and the interactions among the whole software layers should be considered. In this paper, we show the design and implementation of a performance analysis framework that enables hierarchical analysis of performance of Linux-based embedded systems considering interactions among the software layers. By using the proposed framework, we can obtain useful run-time information about a hierarchical software structure which usually consists of user-defined function layer, library function layer, system call layer, and kernel events layer. Experimental results reveal that the proposed framework could accurately identify the performance bottlenecks with the corresponding software layers during executions of target applications through the accompanying sub-steps of the analysis: the actual execution paths, the execution time of each observed event in each software layer, and the control flows across the software layers.