• Journal of KSNVE
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• v.9 no.3
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• pp.600-606
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• 1999

A reactive type acoustic filter is developed based on the phase cancellation effect which is occurring in the plane wave propagation through the two paths where the cross sectional areas are reversely changing. The theory is experimentally validated by the use of a cylindrical duct and an inserted hollowed cone of which vertex part is eliminated. Noise attenuation and the filtered frequency are dependent on the area variation and the effective length of the filter. Experimental comparison shows that the filtered frequencies of 1st and 2nd mode are lower than the analytical prediction due to the mass loading effects, and the 3rd mode is in good agreement. The proposed filter can be applied as an in-duct noise filter for improving the sound quality in a narrow space for various industrial applications.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.252-258
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• 2010

The purpose of this study was to configure a model geared toward predicting factors affecting the sexual behavior of college students and the path of their influence. The standardized path coefficients of factors that might affect their sexual behavior were calculated, and the total effects of the factors were checked when the path of their influence turned out significant. As for the path of the factors affecting the sexual behavior of college students in a firsthand manner, dating exerted a firsthand influence on sexual knowledge. That had the greatest total effect on sexual knowledge, and those with dating experiences had a better sexual knowledge. Sexual knowledge exercised a firsthand influence on sexual attitude, and that had the largest total effect on sexual attitude, as the students who had a better sexual knowledge took a more positive sexual attitude. Sexual roles affected sexual attitude and sexual behavior in a firsthand way, and sexual roles had the biggest total effect on sexual behavior. Androcentric and open sexual attitudes were permissive, distorted and led to more sexual behavior.

• Journal of KIISE:Databases
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• v.30 no.2
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• pp.109-124
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• 2003

Although most commercial relational DBMSs Provide a graphical query language for the user friendly interfaces of the databases, few research has been done for graphical query languages in object databases. Expressing complex query conditions in a concise and intuitive way has been an important issue in the design of graphical query languages. Since the object data model and object query languages are more complex than those of the relational ones, the graphical object query language should have a concise and intuitive representation method. We propose a graphical object query language called GOQL (Graphical Object Query Language) for object databases. By employing simple graphical notations, advanced features of the object queries such as path expressions including set attributes, quantifiers, and/or methods can be represented in a simple graphical notation. GOQL has an excellent expressive power compared with previous graphical object query languages. We show that path expressions in XSQL(1,2) can be represented by the simple graphical notations in GOQL. We also propose an algorithm that translates a graphical query in GOQL into the textual object query with the same semantics. We finally describe implementation results of GOQL in the Internet environments.

• Journal of Internet Computing and Services
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• v.3 no.1
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• pp.41-49
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• 2002

Ohba has suggested the Colored Thread Algorithm to prevent looped path when LSP is to be setup. M immediate node sends thread information such as color, hop count. ill, to downs1ream node via LDP message for the set-up of LSP. Afterward, decides that the looped path is formed when it receives a message with a same colored thread that was sent to downs1ream node, and it searches another path. If the message reaches to the egress node, then acknowledged message is sent to upstream node as reverse direction to the ingress node to set up loop-free path. For the algorithm, Ohva has defined three thread states as Null, Colored, Transparent. In this paper, the state of thread is extended to 5 states such as Extending, Merging, Stalling, Null, and Transparent. By the way, related FSM and TCB was redefined to make clear the ambiguity of thread states which causes faulty actions and to remove overhead. And, to improve performance, it limits to generate a thread in the state of Stalling.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.90-94
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• 1984

We deduced a possible metabolic pathway of L-malate in a malo-alcoholic yeast, Schizosaccharomyces japonicus var. japonicus St-3. The malic enzyme (EC 1.1.1.40) prepared from the microorganism was about four times as active as that of malate dehydrogenase (EC 1.1.1.37). And Km values of malic enzyme and malate dehydrogenase for malate were found to be 3.125 mM and 4.761 mM, respectively, which referred to the fact that the affinity of malic enzyme for the substrate was greater than that of malate dehydrogenase. We also found that pyruvate was produced with disappearing malate in malo-alcoholic fermentation, and that the addition of $Mn^{2+}$ activated malic enzyme activity. Based on these results obtained we have deduced a main pathway of malate${\rightarrow}$pyruvate${\rightarrow}$acetaldehyde${\rightarrow}$ethanol for the utilization of L-malate by this malo-alcoholic yeast strain.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.408-422
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• 2000

In this paper, we propose a generalized vector channel model for wireless communication systems using antenna arrays. The proposed channel model reflects path loss. spatial-temporal variation of shadowing, multipath fading , Doppler effect, spatial distribution of local scatterers and delay spread due to remote dominant scatterers. In addition, we use a discrete ray model in which respective ray signal experiences independent shadowing, fading and Doppler shift, and impinges on antenna arrays at a distinct angle. Based on the proposed mode. we derive the relations on the spatial and temporal correlations of the received signals and implement a spatial channel simulator. By comparing the theoretical values with the simulated ones, we verify the effectiveness of the implemented simulator. The simulator is then used to generate an arbitrary channel impulse response and to analyze the channel characteristics under various environments.

• Journal of the Korea Society of Computer and Information
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• v.26 no.3
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• pp.9-17
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• 2021

In this paper, an autonomous multi-agent path planning using reinforcement learning for monitoring of infrastructures and resources in a computationally distributed system was proposed. Reinforcement-learning-based multi-agent exploratory system in a distributed node enable to evaluate a cumulative reward every action and to provide the optimized knowledge for next available action repeatedly by learning process according to a learning policy. Here, the proposed methods were presented by (a) approach of dynamics-based motion constraints multi-agent path-planning to reduce smaller agent steps toward the given destination(goal), where these agents are able to geographically explore on the environment with initial random-trials versus optimal-trials, (b) approach using agent sub-goal selection to provide more efficient agent exploration(path-planning) to reach the final destination(goal), and (c) approach of reinforcement learning schemes by using the proposed autonomous and asynchronous triggering of agent exploratory phases.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.27-35
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• 2010

War-games using C4I systems have been used to improve the command ability of commanders and the fighting power of combat forces. During a war-game simulation, a commander makes a plan for the movement of a combat force and issues orders to the combat force according to the plan. If it is possible to minimize damages from the artillery of enemy forces and take the advantage position where is effective for attack/defense, we can hold a dominant position of the battlefield. Therefore, this papers proposes a genetic algorithm-based optimal path searching method. The proposed method creates an optimal path of a combat force by taking into consideration dangerous conditions of the battlefield in which the combat force is. This paper also shows the process of creating an optimal path by using a discrete event specification modeling and simulation method.

• Journal of Korean Society of Transportation
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• v.19 no.3
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• pp.101-113
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• 2001

Since late 1970s. one of the principal research areas in transportation problem is dynamic traffic assignment (DTA). Although many models have been developed regarding DTA, yet they have some limits of describing real traffic patterns. This reason comes from the fact that DTA model has the time varying constraints such as state equation, flow propagation constraint, first in first out(FIFO) rule and queuing evolution. Thus, DTA model should be designed to satisfy these constraints as well as dynamic route choice condition, dynamic user equilibrium. In this respect, link-based DTA models have difficulty in satisfying such constraints because they have to satisfy the constraints for each link, while path-based DTA models may easily satisfy them. In this paper we develop a path-based DTA model. The model includes point queue theory to describe the queue evolution and simulation loading method for depicting traffic patterns in more detail. From a numerical test, the model shows promising results.

• Journal of KIISE:Databases
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• v.35 no.4
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• pp.356-367
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• 2008

As XML is gaining unqualified success in being adopted as a universal data representation and exchange format, particularly in the World Wide Web, the problem of querying XML documents poses interesting challenges to database researcher. Several structural XML query processing methods, including XISS and XR-tree, for past years, have been proposed for fast query processing. However, structural XML query processing has the problem of requiring expensive Join cost for twig path query Recently, sequence matching based XML query processing methods, including ViST and PRIX, have been proposed to solve the problem of structural XML query processing methods. Through sequence matching based XML query processing methods match structured queries against structured data as a whole without breaking down the queries into sub queries of paths or nodes and relying on join operations to combine their results. However, determining the structural relationship of ViST is incorrect because its numbering scheme is not optimized. And PRIX requires many processing time for matching LPS and NPS about XML data trees and queries. Therefore, in this paper, we propose efficient sequence matching method u sing the bottom-up query processing for efficient XML query processing. Also, to verify the superiority of our index structure, we compare our sequence matching method with ViST and PRIX in terms of query processing with linear path or twig path including wild-card('*' and '//').