• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.5
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• pp.1316-1332
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• 2012

Formation flying is an important technology that enables high cost-effective organization of outer space aircrafts. The ad-hoc wireless network based on direct-sequence ultra-wideband (DS-UWB) techniques is seen as an effective means of establishing wireless communication links between aircrafts. In this paper, based on the theory of matched filter and error bits correction, a hybrid detection algorithm is proposed for realizing multiuser detection (MUD) when the DS-UWB technique is used in the ad-hoc wireless network. The matched filter is used to generate a candidate code set which may contain several error bits. The error bits are then recognized and corrected by an novel error-bit corrector, which consists of two steps: code mapping and clustering. In the former step, based on the modified optimum MUD decision function, a novel mapping function is presented that maps the output candidate codes into a feature space for differentiating the right and wrong codes. In the latter step, the codes are clustered into the right and wrong sets by using the K-means clustering approach. Additionally, in order to prevent some right codes being wrongly classified, a sign judgment method is proposed that reduces the bit error rate (BER) of the system. Compared with the traditional detection approaches, e.g., matched filter, minimum mean square error (MMSE) and decorrelation receiver (DEC), the proposed algorithm can considerably improve the BER performance of the system because of its high probability of recognizing wrong codes. Simulation results show that the proposed algorithm can almost achieve the BER performance of the optimum MUD (OMD). Furthermore, compared with OMD, the proposed algorithm has lower computational complexity, and its BER performance is less sensitive to the number of users.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.3
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• pp.1-6
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• 2009

Since the success of the first flight, vast advancements have been made to the aircrafts with recent developments incorporating highly complex mechanisms, placing greater emphasis on the competence of the pilot. Studies are currently being undertaken to effectively source the trainee pilots with the most ideal level of aptitude for aviation with an aim to optimise the selection process with focus on economy and time, while research into identifying the optimal human characteristics for aviation is being done. As part of the selection process, number of tests is arranged with focus on the individual competence, suitability for flight, health status, aptitude and intelligence with the results of the tests used as reference materials during the selection procedure. This study has investigated the effect the academic competence has on the aptitude for aviation amongst many other abilities of human beings and the findings show that higher levels of aptitude have been demonstrated by the students who have displayed academic excellence across all the courses with statistics pointing to a positive correlation between the two subjects. This supports the theory that students who are academically superior have higher probability of being found to possess greater level of flight aptitude. The outcome of the study iterates the fact that academic competence of the students should not be regarded lightly in the selection process. Based on the current study, it is believed that a research into determining the relationship between the SAT results, average yearly grade and flight aptitude will help identify the key factors in possessing high level of flight aptitude with greater certainty.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.8
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• pp.524-535
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• 2006

With rapid development of Internet technology, business management in an organization or an enterprise depends on Internet-based technology for the most part. Furthermore, as dependency and cohesiveness of network in the communication facilities are increasing, cyber attacks have been increased against vulnerable resource in the information system. Hence, to protect private information and computer resource, research for damage propagation is required in this situation. However the proposed traditional models present just mechanism for risk management, or are able to be applied to the specified threats such as virus or worm. Therefore, we propose the probabilistic model of damage propagation based on the Markov process, which can be applied to diverse threats in the information systems. Using the proposed model in this paper, we can predict the occurrence probability and occurrence frequency for each threats in the entire system.

• Journal of the Korean Geographical Society
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• v.45 no.5
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• pp.609-627
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• 2010

Finding the ideal location for your business is one of the most critical and important steps you will have to undertake. Otherwise, done in the wrong way you will only end up paying an expensive cost for an unsuitable location. Therefore to select the perfect location for your business, this study makes a reasonable and simple model for retail shops by calculating occupation population for each store applying Huffs "Probability Theory" to Hypermarket in Seoul. Then this study, based on occupation population, has divided every unit section (dong scale) into 4 market types which represent the state of the competitive markets, including monopoly, oligopoly, competitive, and noncompetitive markets. Consequently, the most reasonable place to locate a new store is where it can take most of the customers, that is, a place which can take non-competitive market as much as possible and is distant far enough from competitive market where competition is severe.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1062-1069
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• 2009

The kidney diseases is a big social problem what is suffering sequela of metabolic syndrome due to obesity. Therefore, it is most important that early to take the appropriate action; it does not have symptoms Abnormalities of the kidney. With this, in mind, this paper wish to propose the method to can diagnosis by non self-consciousness, non-imprisonment, analgesia of kidney disease through the voice analysis. To configure the entire system is developed to combines the voice analysis, watching the face color and this paper is designed the method to diagnosis kidney disease based on labial. In this paper, organized each kidney disease patients and healthy people group and we would like to analyze, compare with output in experiment morphology analysis and numerical value analysis of voice information. Secondly, auscultation theory of Oriental medicine and linguistic, phonetics analyze out interrelation to extraction peculiar elements of kidney about voice deduction deduced relation of the first formants frequency. Such result of experimentation, deduced widely to be formed the first formants frequency bandwidth value of kidney patients group than normal group. Finally, diagnosing an kidney diseases in only labial sound, calculated about misdiagnosis probability.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.59-67
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• 2015

Because reservoirs that supply irrigation water play an important role in water resource management, it is necessary to evaluate the vulnerability of this particular water supply resource. The purpose of this study is to provide water supply risk maps of agricultural reservoirs in South Korea using irrigation vulnerability model and cluster analysis. To quantify water supply risk, irrigation vulnerability indices are estimated to evaluate the performance of the water supply on the agricultural reservoir system using a probability theory and reliability analysis. First, the irrigation vulnerability probabilities of 1,346 reservoirs managed by Korea Rural Community Corporation (KRC) were analyzed using meteorological data on 54 meteorological stations over the past 30 years (1981-2010). Second, using the K-mean method of non-hierarchical cluster analysis and pre-simulation approach, cluster analysis was applied to classify into three groups for characterizing irrigation vulnerability in reservoirs. The morphology index, watershed area, irrigated area, and ratio between watershed and irrigated area are selected as the clustering analysis parameters. It is suggested that the water supply risk map be utilized as a basis for the establishment of risk management measures, and could provide effective information for a reasonable decision making on drought risk mitigation.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4084-4092
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• 2012

Theoretical calculations based on density functional theory (DFT) were performed to study the substituent effect on the geometric and electronic structures as well as the biological behavior of technetium-99m-labeled diphosphonate complexes. Optimized structures of these complexes are surrounded by six ligands in an octahedral environment with three unpaired 4d electrons ($d^3$ state) and the optimized geometry of $^{99m}Tc$-MDP agrees with experimental data. With the increase of electron-donating substituent or tether between phosphate groups, the energy gap between frontier orbitals increases and the probability of non-radiative deactivation via d-d electron transfer decreases. The charge distribution reflects a significant ligand-to-metal electron donation. Based on the calculated geometric and electronic structures and biologic properties of $^{99m}Tc$-diphosphonate complexes, several structure-activity relationships (SARs) were established. These results may be instructive for the design and synthesis of novel $^{99m}Tc$-diphosphonate bone imaging agent and other $^{99m}Tc$-based radiopharmaceuticals.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.271-280
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• 2002

A probabilistic approach to identify the effects of uncertainties of soil strength parameters on searching a critical slip surface with the lowest reliability is introduced. In general construction field, it is impossible for the engineer to always gather a variety of statistical information of soil strength parameters for which lots of laboratory and in-situ soil testing are required and to use it with enough statistical knowledge. Thus, in order that the engineer may easily understand the probabilistic concept for the slope stability analysis, this study proposes a combined procedure to incorporate the engineering probabilistic tools into the existing deterministic slope stability analysis methods. Using UTEXAS 3, a slope stability analysis computer program developed by U.S. Army Corps of Engineers (U.S. COE), this study provides the results of this probabilistic slope stability analysis in terms of probability of failure or reliability index. This probabilistic method f3r slope stability analysis appears to yield more comprehensive results of slope reliability than does existing deterministic methods with safety factors alone.

• Strategy21
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• s.44
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• pp.103-141
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• 2018

As the South China Sea maritime dispute illustrates, when considering the place where maritime claims occur, states do not have many choices to respond to maritime claims in which disputed areas are located far away from the land and are surrounded by the sea. As Mearsheimer (2014) points out, the sea stops power projection. Therefore, in order to adopt coercive as well as peaceful settlement policies to deal with maritime claims, states need to overcome obstacles (the sea) to project power. It means that if states want to conduct a specific foreign policy action, such as negotiating maritime borderlines or arguing sovereignty on islands, they need a tool (naval power) to coerce or to persuade the opponent. However, there are lack of research that studies maritime claims from the perspective of naval power. This research project fills this gap based on naval power. How do relative levels of naval power and (dis) parities of naval power influence the occurrence of MIDs over maritime claims? Naval power is a constitutive element during maritime claims. If disputants over maritime claims have required naval power to project their capability, it means that they have the capability to apply various ways, such as aggressive options including MIDs, to accomplish their goals. So, I argue that when two claimants have enough naval power to project their capabilities, the likelihood of MIDs over maritime claims increases. Given that one or both states have a certain level of naval power, how does relative naval power between two claimants influence the management of maritime claims? Based on the power transition theory, I argue that when the disparities of relative naval power between claimants becomes distinctive, militarized conflicts surrounding maritime territory are less probable. Based on the ICOW project which codes maritime claims from 1900 to 2001, the empirical results of the Poisson models show if both claimants have projectable naval power, the occurrence of MIDs over maritime claims increases. In addition, the result shows that when disputants maintain similar relative naval powers, they are more likely to initiate MIDs over maritime claims. To put it differently, if naval capabilities' gap between two claimants becomes larger, the probability of the occurrence of MIDs decreases.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.5_6
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• pp.280-289
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• 2003

Deadlock recovery-based routing algorithms in wormhole networks have gained attraction due to low hardware complexity and high routing adaptability Progressive deadlock recovery techniques require a few dedicated resources to transmit deadlocked packets rather than killing them. Selection of deadlocked packets is primarily based on time-out value which should be carefully determined considering various traffic patterns or packet length. By its nature, current techniques using time-out accompany unignorable number of false deadlock detections especially in a heavy-loaded network or with long packet size. Moreover, when a deadlock occurs, more than one packet may be marked as deadlocked, which saturate the resources allocated for recovery. This paper proposes more accurate deadlock detection scheme which does not make use of time-out to declare deadlock. The proposed scheme reduces the probability to detect false deadlocks considerably. Furthermore, a single message is selected as deadlocked for each cycle of blocked messages, thereby eliminating recovery overheads.