• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.4
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• pp.310-318
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• 2008

This paper presents a parallel typed walking robot to improve walking space and stability region. The robot is designed by inserting an intermediate mechanism between upper leg mechanism and lower leg mechanism. The leg mechanism is composed of three legs and base, which form a parallel mechanism with ground. Seven different types of walking robot are invented by combining the leg mechanisms and an intermediate mechanism. Topology is applied to design the leg mechanism. A motor vector is adopted to determine Jacobian and a wrench vector is used to analyze dynamics of the robot. We explore the stability region of the robot from the reaction force of legs and compute ZMP including the holding force to contact the foot to a wall. This investigates a walking stability when the robot walks on the ground as well as on the wall. We examine the walking space generated by support legs and by swing legs. The robot has both a large positional walking space and a large orientational walking space so that it can climb from a floor up to a wall.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.421-429
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• 2006

Recently, DHT-based Structured P2P System have a attention to scalability and providing efficient lookup by routing. Retrieving content of DHT-based P2P require knowledge of the exact identifier of sharing file. But user may wish to search for sharing file using descriptive keyword or content. To resolve the problem, this paper propose Extended-CAN mechanism to support keyword search. We defined content-based keyword and identifier of sharing file, and PLS extended to KID and CKD for keyword, common keyword processing. As a result, Extended-CAN mechanism provide efficient keyword search for DHT-based Structured P2P System.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.379-388
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• 1998

In this paper we propose a DMR-II shared-medium access control protocol which was developed for the ATM access network users to support isochronous and non-isochronous traffics simultaneously under the bandwidth sharing environment, and describe its architecture and operation principles. The DMR-II protocol uses the slotted-ring topology, and gives the higher transmission priority to the isochronous traffic than the non-isochronous traffic. To support the isochronous traffic it uses the slot reservation mechanism, and maintains the delay variation of the isochronous traffic beyond the threshold value by using the blocking mechanism whenever the total user traffic overflows the network's bandwidth limitation. for the non-isochronous traffic the DMR-II protocol lets all the nodes to have fair transmission chances by using the reset mechanism based on the window counter scheme.

• Industrial Engineering and Management Systems
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• v.7 no.1
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• pp.57-65
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• 2008

Available-to-promise (ATP) exhibiting availability of manufacturing resources can be used to support customer order promising. Recently, one advanced function called Capable-to-promise (CTP) is provided by several modern APS (advanced planning system) that checks available capacity for placing new production orders or increasing already scheduled production orders. At the customer enquiry stage while considering the order delivery date and quantity to quote, both ATP and CTP are allocated to support order promising. In particular, current trends of mass customization and multi-side production chain derive several new constraints that should be considered when ATP/CTP allocation planning for order promising - such as customer's preference plants or material vendors, material compatibility, etc. Moreover, ATP/CTP allocation planning would be executed over a rolling time horizon. To utilize capacity and material manufacturing resource flexibly and fulfill more customer orders, ATP/CTP rolling planning should possess resource reallocation mechanism under the constraints of order quantities and delivery dates for all previous order promising. Therefore, to enhance order promising with reliability and flexibility to reallocate manufacturing resource, the ATP/CTP reallocation planning mechanism is needed in order to reallocate material and capacity resource for fulfilling all previous promised and new customer orders beneficially with considering new derived material and capacity constraints.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1128-1145
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• 2022

Owing to the rapid development of information science, data analysis based on machine learning has become an interdisciplinary and strategic area. Marine predators algorithm (MPA) is a novel metaheuristic algorithm inspired by the foraging strategies of marine organisms. Considering the randomness of these strategies, an improved algorithm called co-evolutionary cultural mechanism-based marine predators algorithm (CECMPA) is proposed. Through this mechanism, search agents in different spaces can share knowledge and experience to improve the performance of the native algorithm. More specifically, CECMPA has a higher probability of avoiding local optimum and can search the global optimum quickly. In this paper, it is the first to use CECMPA to perform feature subset selection and optimize hyperparameters in support vector machine (SVM) simultaneously. For performance evaluation the proposed method, it is tested on twelve datasets from the university of California Irvine (UCI) repository. Moreover, the coronavirus disease 2019 (COVID-19) can be a real-world application and is spreading in many countries. CECMPA is also applied to a COVID-19 dataset. The experimental results and statistical analysis demonstrate that CECMPA is superior to other compared methods in the literature in terms of several evaluation metrics. The proposed method has strong competitive abilities and promising prospects.

• Geomechanics and Engineering
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• v.29 no.2
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• pp.193-205
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• 2022

The face stability of shield tunnelling is the most important control index for safety risk management. Based on the reliability of the transparent clay (TC) model test, a series of TC model tests under different buried depth were conducted to investigate the progressive failure mechanism of tunnel face. The support pressure was divided into the rapid descent stage, the slow descent stage and the basically stable stage with company of the local failure and integral failure in the internal of the soil during the failure process. The relationship between the support pressure and the soil movement characteristics of each failure stage was defined. The failure occurred from the soil in front of the tunnel face and propagated as the slip zone and the loose zone. The fitted formulas were proposed for the calculation of the failure process. The failure mode in clay was specified as the basin shape with an inverted trapezoid shape for shallow buried and appeared as the basin shape with a teardrop-like shape in deep case. The implications of these findings could help in the safety risk management of the underground construction.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.733-740
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• 2005

In this paper, we propose an approach to transport layer mobility support leveraging the SCTP extension dubbed dynamic address reconfiguration in IPv6 networks. Timing issues related to the end-to-end address management, and a novel error recovery mechanism associated with a handover are discussed. The proposed error recovery mechanism is analyzed and compared to that of the plain SCTP to show that it reduces the handover latency and error recovery time.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.279-282
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• 2007

Typically a wireless sensor network consists of a number of nodes that sense surrounding environment and collaboratively work to process and route the sensing data to a sink or gateway node. We propose an architecture with support of multiple routers in IPv6-based Low-power Wireless Personal Area Network (6LoWPAN). Our architecture provides traffic load balancing and increases network lifetime as well as self-healing mechanism so that in case of a router failure the network still can remain operational. Each router sends its own Router Advertisement message to nodes and all the nodes receiving the messages can select which router is the best router with the minimum hop-count and link information. We have implemented the architecture and assert our architecture helps in traffic load balancing and reducing data transmission delay for 6LoWPAN.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.3
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• pp.342-348
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• 2004

As the advent of the Internet, B2B negotiation process on the Internet has been given attention from both researchers and practitioners. However, literature still shows that only structured conditions have been explicitly considered, despite the fact that unstructured conditions should be rendered as well. In this sense, this paper proposes a new negotiation support mechanism to incorporate causal relationships between structured and unstructured conditions in the process of B2B negotiation. Fuzzy cognitive map was used as a main source of causal knowledge as well causal inference engine. A prototype named CAKES-NEGO was developed to perform experiments with an illustrative example. Results revealed the robustness of our proposed negotiation support mechanism.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.151-152
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• 2006

Nowadays, great attention has been shown to the question of ultrasonic linear motor for accomplishing the high positioning accuracy and high driving force in the semiconductor and optical industry. Ultrasonic linear motors have many advantages such as simple structure, quick response, ability to maintain position without energy consumption, and electromagnetic effect. And BLT has attracted attention to accomplish large vibration amplitude and large mechanical force. Authors designed and developed the new type of ultra sonic linear motor with multi support mechanism, achieved 75N of output force and 0.45m/s of velocity.