• The Journal of Information Systems
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• v.28 no.2
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• pp.53-72
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• 2019

Purpose The purpose of this study is to examine the impact of tie strength in the network of industrial clustering on the knowledge acquisition, integration and innovation performance of small and medium sized enterprises. We test the positive relationship of weak tie and knowledge acquisition, strong tie and knowledge integration, and the interaction effect of two tie strengths on both processes of knowledge acquisition and integration. By identifying these relationships, we can better understand how to manage the attributes of social networks in terms of tie strength in order to improve the performance of innovation for the small and medium sized enterprises. Design/methodology/approach We collect 200 survey data from 2 industrial cluster respectively: Pankyo and Guroo. In Pankyo, the proportion of IT industry is the highest (35%) while the proportion of manufacturing is highest (35%) in Guroo. Pooling the data from two industrial cluster, we check the reliability and validity of our research model and test the hypotheses. Findings First, we find the positive relationship of weak tie and knowledge acquisition from both industrial clustering. Weak tie is composed of heterogeneous organizations with various background and expertise. The communication and information sharing of organizations in the weak tie network helps the idea generation for organization's innovation, which is the knowledge acquisition process. Second, the relationship of strong tie and knowledge integration is insignificant. Typically the strong tie from long-lasting partnership is expected to be beneficial in the action stage of innovation, which is the knowledge integration process. However it is not identified in our industry cluster. Finally, the interaction effect of weak and strong tie is identified to be effective on both knowledge acquisition and integration processes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4436-4452
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• 2015

The IEEE 802.15.6 standard is introduced to satisfy all the requirements for monitoring systems operating in, on, or around the human body. In this paper, analytical models are developed for evaluating the performance of the IEEE 802.15.6 CSMA/CA-based medium access control protocol for wireless body area networks (WBAN) under unsaturation condition. We employ a three-dimensional Markov chain to model the backoff procedure, and an M/G/1/K queuing system to describe the packet queues in the buffer. The throughput and delay performances of WBAN operating in the beacon mode are analyzed in heterogeneous network comprised of different user priorities. Simulation results are included to demonstrate the accuracy of the proposed analytical model.

• Korean Journal of Medicinal Crop Science
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• v.11 no.4
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• pp.259-263
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• 2003

This study was carried out to get basic information about the morphological and production characteristics of fennel populations different origin under different ecological conditions in Hungary. The Korean population can be registered as a medium high genotype and showed a more accelerated growth characters than Hungarian taxon and the two populations have a medium homogeneity $(CV\;=\;4{\sim}22%)$. In the second year plant height in Hungarian taxon was significantly higher than that of the Korean population. The shooting dynamic of individual plants might be heterogeneous in both taxa and the Korean population was not only shorter in the height but had also less shoots by 16% than the Hungarian one. The Hungarian taxon exceeded the umbel size and numbers to the Korean one (by 3.62 cm in the average) and the variability in the populations was high $(CV\;=\;29{\sim}49%)$. Seed size was proved to be also a discriminative feature between the examined taxa. With small deviations (CV < 2) the Hungarian population produced seeds longer by 38%. Homogeneity in the populations was dependent more on the vegetation years and on the characteristics measured but less on the origins, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2499-2522
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• 2017

Multi-hop networks are a low-setup-cost solution for enlarging an area of network coverage through multi-hop routing. Carrier sense multiple access with collision avoidance (CSMA/CA) is frequently used in multi-hop networks. Multi-hop networks face multiple problems, such as a rise in contention for the medium, and packet loss under heavy-load, saturated conditions, which consumes more bandwidth due to re-transmissions. The number of re-transmissions carried out in a multi-hop network plays a major role in the achievable quality of service (QoS). This paper presents a statistical, analytical model for the end-to-end delay of contention-based medium access control (MAC) strategies. These strategies schedule a packet before performing the back-off contention for both differentiated heterogeneous data and homogeneous data under saturation conditions. The analytical model is an application of Markov chain theory and queuing theory. The M/M/1 model is used to derive access queue waiting times, and an absorbing Markov chain is used to determine the expected number of re-transmissions in a multi-hop scenario. This is then used to calculate the expected end-to-end delay. The prediction by the proposed model is compared to the simulation results, and shows close correlation for the different test cases with different arrival rates.

• Macromolecular Research
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• v.15 no.7
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• pp.633-639
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• 2007

A variety of NMR techniques were applied to the micro-chemical structural characterization of polyanilines prepared via an efficient synthetic method in a self-stabilized dispersion medium in which the polymerization was conducted in a heterogeneous organic/aqueous biphasic system without any stabilizers. Here, the monomer and growing polymer chain were shown to function simultaneously as a stabilizer, imparting compatibility for the dispersion of the organic phase, and as a form of flexible template in an aqueous reaction medium. Polymerizations predicated on this concept generated polyanilines with a low defect content: solution state $^{13}C-NMR$ and solid $^{13}CDD/CP/MAS$ spectroscopy indicated that the synthesized HCPANi and its soluble derivative, HCPANi-t-BOC, evidenced distinctly different NMR spectra with fewer side peaks, as compared to conventionally prepared PANis, and the complete structural assignments of the observed NMR peaks could be determined via the combination of both 1D and 2D techniques. Ortho-linked defects in HCPANi were estimated to be as low as 7%, as shown by a comparison of the integration of the carbonyl carbon resonance peaks.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.411-419
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• 2016

This article investigates the problem of distributed channel selection in opportunistic spectrum access networks from a perspective of interference minimization. The traditional physical (PHY)-layer interference model is for information theoretic analysis. When practical multiple access mechanisms are considered, the recently developed binary medium access control (MAC)-layer interference model in the previous work is more useful, in which the experienced interference of a user is defined as the number of competing users. However, the binary model is not accurate in mathematics analysis with poor achievable performance. Therefore, we propose a real-valued one called stochastic MAC-layer interference model, where the utility of a player is defined as a function of the aggregate weight of the stochastic interference of competing neighbors. Then, the distributed channel selection problem in the stochastic MAC-layer interference model is formulated as a weighted stochastic MAC-layer interference minimization game and we proved that the game is an exact potential game which exists one pure strategy Nash equilibrium point at least. By using the proposed stochastic learning-automata based uncoupled algorithm with heterogeneous learning parameter (SLA-H), we can achieve suboptimal convergence averagely and this result can be verified in the simulation. Moreover, the simulated results also prove that the proposed stochastic model can achieve higher throughput performance and faster convergence behavior than the binary one.

• Economic and Environmental Geology
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• v.27 no.3
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• pp.281-287
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• 1994

The present paper deals with numerical modeling of Love channel waves in transversely isotropic elastic medium. First, an explicit finite-difference scheme of second order approximation is formulated with the wave equation of SH particle displacement in transversely isotropic medium. Since it is a heterogeneous formulation, it should enable efficient modeling of complex model structures without additional treatment of the internal boundary matching. With a model of isotropic coal seam embedded in high velocity host rock, seismograms are synthesized and tutn out to be essentially identical with published ones of Korn and $St{\ddot{o}}ckl$. Next, anisotropic coal seams are investigated. It is found that the horizontal velocity of the seam appears to play a major role of determining the group velocity of Love channel waves. The group velocity increases with the increase of the horizontal velocity or vice versa. However, further study will be needed to exploit fully Love channel waves for the determination of lithology, stratification, fracture in sedimentary rocks, for instance, for hydrocarbon exploration and development.

• Applied Microscopy
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• v.18 no.2
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• pp.167-176
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• 1988

Extrachromosomal circular DNA complexes from erythrocytes and splenocytes isolated from Carassius carassius were examined by mica-press-absorption method. The method was described that released small polydisperse circular DNA molecules in situ from the erythrocytes and the splenocytes and that allows selective observation of the small circular DNA complexes bound to cellular components. The released polydisperse circular DNA complexes were absorbed preferentially on mica in a divalent cation-free medium then processed for electron microscopy. Small circular DNAs showed a heterogeneous size distribution of $2{\sim}10{\mu}m$ with a mean contour length of $4.3{\mu}m$ for the circulating erythrocytes and that of $0.7{\sim}3.6{\mu}m$ with a mean contour of length $2.04{\mu}m$ for the splencytes. Cells contained $100{\sim}300$ copies and $300{\sim}700$ copies obtained from the erythrocytes and the splenocytes, repectively. Possible biological functional implications for size distribution of extrachromosomal circular DNAs are discussed.

• Publications of The Korean Astronomical Society
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• v.9 no.1
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• pp.111-166
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• 1994

I have developed a UV and visible spectroscopic database (UVSD) for atoms and molecules, which are found in interstellar medium, stars, galaxies, and in the atmospheres of the earth, planets, satellites, and comets. This UV and visible database, which is machine-readable, consists of three different sub-databases depending upon the characteristics of the sub-databases: (A) atomic and molecular line listings from laboratory observations or theoretical studies; (B) absorption spectra measured in laboratories; and (C) solar UV, visible, and infrared spectral atlases. The UVSD is in a very initial stage of development compared with other well organized and established infrared and microwave databases. In order to make a good quality and complete database, substantial efforts should be made for the acquisition of scattered important data from laboratories or institutions, and then the acquired heterogeneous data should be peer-reviewed and standardized.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.307-311
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• 2004

The unsaturated zone is a significant pathway of the surface contaminant movement and is a highly heterogeneous medium. Therefore, there are limitations in applying conventional convection-dispersion equation(CDE). Artificial neural network(ANN) is considered to be a versatile tool for approximating complex functions. For evaluating the applicability of ANN, numerical tests using ANN were conducted with training set generated by HYDRUS-2D which is based on CDE. The results represent that ANN can estimate the solute transport and the choice of network parameters and generation of training set patterns are important for efficient estimation.