• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.149-155
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• 2003

In this study, we introduce the main ideas on the control and strategy used by the robot soccer team of the Universidad de Buenos hires, UBA-Sot. The basis of our approach is to obtain a cooperative behavior, which emerges from homogeneous sets of individual behaviors. Except for the goalkeeper, the behavior set of each robot contains a small number of individual behaviors. Basically, the individual behaviors have the same core: to move from the initial to-ward the target coordinates. However, these individual behaviors differ because each one has a different precondition associated with it. Each precondition is the combination of a number of elementary ones. The aim of our approach is to answer the following questions: How can the robot compute the preconditions in time\ulcorner How are the control actions defined, which allow the robot to move from the initial toward the final coordinates\ulcorner The way we cope with these issues is, on the one hand, to use ball and robot predictors and, on the other hand, to use very fast planning. Our proposal is to use planning in such a way that the behavior obtained is closer to a reactive than a deliberative one. Simulations and experiments on real robots, based on this approach, have so far given encouraging results.

• Journal of the Korean Geographical Society
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• v.39 no.1
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• pp.116-131
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• 2004

The purpose of this study is to inquiry spatial features of shipbuilding subcontract structures. These days, firms are trying to get their goals by wav of production system which is related to other firm. Shipbuilding subcontract structures which builds complex and grand plant show a different peculiarity according to spatial features having rules of business relations with contracting firms. First of all, internal subcontracting firms which takes part in the production process of contracting firm and shipbuilding cooperative complex firms which showing a peculiarity of spin-off firms are closely related with contracting firm. And firms in Changwon that have a specialized with machine industry and those of Busan that have made development in marine equipment industries traditionally are connected with subcontract relations because of a high level of specialization relatively. On the other hand, subcontracting firms which range from non-localized and provide standardized products are less connected with contracting firm. In order to develop of Korea' shipbuilding industry, first, close cooperative relation is important with subcontracting firms which concentrate internal and outside contacting firm. And, it is necessary to strengthen selective business relations with far distance firms which are specialized in technology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3430-3438
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• 2011

The purpose of this study is to set the Korean mandarine quality standards based on consumer preference survey. Until now the Korean mandarine's quality standards has been based on the fruit size. The Korean mandarine's quality in agricultural cooperative, citrus agricultural cooperative federation, and some agricultural corporation has been selected in accordance with its own brand of quality grade using a non-destruction sorting machine. But, setting the Korean mandarine's quality standards has been based on the convenient and routine method rather than the scientific and objective method, consumer's preference. According to the grade contents, the highest grade brand was required more than sugar $12^{\circ}Bx$ and less than acid 1.0% and the following grade brand was required more than sugar $11^{\circ}Bx$ and less than acid 1.0% uniformally. Thus, in this study, based on the consumers' preference of Korean mandarine, 4-level grades of sugar and 4-level grades of acidity were divided into the total 16-level grades. Based on them, 5-level grades were set.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.677-683
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• 2009

In this study, we designed and implemented testbed for localization algorithm by using a area reduction method in outdoor environment. The proposed algorithm used 3 steps of area reduction method, which estimated blind nodes position. Also, we have experimented with using a Zigbee module for 5 fixed reference nodes and 4 blind nodes in sensor field of $60m{\times}23m$. The results show that our algorithm is improved the localization accuracy even at the number of ref. node is fixed and the number of blind node is increased. In future research, we will be adding the function of seamless localization in indoor and NLOS(non-line of sight) environment.

• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.49-55
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• 2015

In cognitive radio network (CRN), spectrum sensing is an elementary level of technology for non-interfering to licensed user. Required sample number for spectrum sensing is directly related to the throughput of secondary user and makes the tradeoff between the throughput of secondary user and interference to primary user. Required spectrum sensing sample is derived from required false alarm, detection probability and minimum required SNR of primary user (PU). If we make clustering and minimize the required transmission boundary of secondary user (SU), we can relax the required PU SNR for spectrum sensing because the required SNR for PU signal sensing is related to transmission range of SU. Therefore we can achieve efficient throughput of CRN by minimizing spectrum sensing sample. For this, we design the tradeoff between gain and loss could be obtained from clustering, according to the size of cluster members through game theory and simulation results confirm the effectiveness of the proposed method.

• Journal of The Korean Association For Science Education
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• v.39 no.6
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• pp.695-706
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• 2019

This study conducted a case study on the process-centered evaluation competency of a middle-school/high-school science teacher using Teacher's Process-centered Evaluation Competency (T-PEC) measurement tool. The case analysis shows that teacher A in a middle school represents high competency of process-centered evaluation planning and cooperative communication while the competency of utilizing process-centered evaluation results is low owing to the characteristics of non-standardized areas. Teacher B in a high school shows high level of cooperative communication competency whereas low level of process-centered evaluation execution competency because the freedom given to students is not enough during the process of evaluation. The teacher also shows very low level of utilizing process-centered evaluation results due to the lack of time and the school culture not giving feedback to the students. According to cross-case analysis, teacher A and B both represent the highest level of collaborative communication competency and the lowest level of utilization process-centered evaluation results competency. And the lack of clear criteria for process-centered evaluation leads to different understanding of process-centered evaluation between the two teachers, and teacher B shows low the level of utilizing process-centered evaluation affects results due to the students not being concerned on feedback, security problem, and the reality focusing on the university entrance examination in high schools. Based on the results, this study suggests providing clear guidelines of process-centered evaluation to teachers, introducing an application in order to solve the time-lack problem pointed out as the biggest problem of process-centered evaluation, ensuring objectivity and security about process-centered evaluation results, and building the school culture such as the expanded application of standardized areas in order to implementing process-centered evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.7
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• pp.372-379
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• 2014

When a hand-held device with limited battery transmits and receives data using short-range wireless communication systems, such as WLAN(Wireless Local Area Network) or high speed WPAN(Wireless Personal Area Network), instead of mobile communication systems, the device is able to reduce the power consumption due to the reduced transmission distance. However, if there are many WLAN or high speed WPAN systems around the device, non-negligible power may be consumed by receiving and decoding the packets which have nothing to do with the device. In this paper, we propose a scheme reducing the power consumption by including physical-layer ID in WLAN or WPAN packets and avoiding unnecessary packet receptions. Also, we describe a method to determine the optimum number of physical-layer IDs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.1-9
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• 2011

In this paper, we propose an efficient method to create clusters of geographically distributed base stations which cooperatively transmit signals in cellular mobile communication systems. The proposed method utilizes a sequential selection approach to choose candidate base stations which can provide maximum weighted sum-rate gain when they participate in the cooperative transmission with the existing cluster. In particular, the proposed method limits the maximum number of base stations in a cluster by considering the system operational and implementation complexities. Moreover, the combinations of clusters dynamically change along with variations of channel environments. Through computer simulations, performance of the proposed method is verified by comparing with the non-cooperative transmission method and the static clustering method. Numerical result shows that the proposed sequential selection based clustering method is especially advantageous for the performance improvement of lower percentile users in terms of average throughput, and thus the proposed method can effectively improve the fairness among users.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1173-1179
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• 2012

In this paper, collision avoidance beamforming(CA-BF) technology is proposed to mitigate inter-cell interference in cooperative wireless communications system with limited feedback. Each acess terminal(AT) selects both the best BF weight vector for a serving base transceiver station(BTS) and the most interfering BF weight vectors of interfering BTSs within a cluster, and sends it back to a cluster scheduler. At the cluster scheduler, a set of transmit BF weights of BTSs and the corresponding scheduled ATs are jointly determined to avoid collision among beams formed by BTSs within a cluster, which enhances system throughput by mitigating inter-cell interference. It is shown that the proposed CA-BF outperforms existing non-coordinated BF schemes in terms of the average system throughput.

• BMB Reports
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• v.31 no.1
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• pp.25-30
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• 1998

Kinetic studies of L-Alanine dehydrogenase from Bacillus subtilis-catalyzed reactions in the presence of $Zn^{2+}$ were carried out. The substrate (L-alanine) saturation curve is hyperbolic in the absence of the metal ion but it becomes sigmoidal when $Zn^{2+}$ is added to the reaction mixture indicating the positive cooperative binding of the substrate in the presence of zinc ion. The cooperativity of substrate binding depends on the xinc ion concentration: the Hill coefficients ($n_H$) varied from 1.0 to 1.95 when the zinc ion concentration varied from 0 to $60\;{\mu}m$. The inhibition of AlaDH by $Zn^{2+}$ is reversible and noncompetitive with respect to $NAD^+$ ($K_i\;=\;5.28{\times}10^{-5}\;M$). $Zn^{2+}$ itself binds to AlaDH with positive cooperativity and the cooperativity is independent of substrate concentration. The Hill coefficients of substrate biding in the presence of $Zn^{2+}$ are not affected by the enzyme concentration indicating that $Zn^{2+}$ binding does not change the polymerization-depolymerization equilibria of the enzyme. Among other metal ions, $Zn^{2+}$ appears to be a specific reversible inhibitor inducing conformational change through the intersubunit interaction. These results indicate that $Zn^{2+}$ is an allosteric competitive inhibitor and substrate being a non-cooperative per se, excludes the $Zn^{2+}$ from its binding site and thus exhibits positive cooperativity. The allosteric mechanism of AlaDh from Bacillus subtilis is consistent with both MWC and Koshland's allosteric model.