• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.304-309
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• 1997

Elastic elements, at first, were extensively used in suspensions as vibration isolators at joints. Nowadays they are used to improve stability and handling. The design of these elements has become a very important matter since the loading condition of the mechanism gives a mew suspension geometry without any modification. This paper presents an analysis of forces and moments of joints with elastic elements in the McPherson suspension mechanism to evaluate accurately the elastic deformation using the displacement matrix method in conjunction with the equilibrium equations. First the suspension is modeled as a multi-loop spatial rigid-body guidance mechanism which has elastic elements at the hardpoints of the suspension. Then a method and design euqations are developed to analyze the suspension characteristics by the various tire load. Also the displacement matrices and constraint equations for links are appllied to determine the sensitivity of the suspension mechanism. Finally this approach may conduct a realistic design of suspension mechanisms with elastic elements to improve the performance of the automobile under various driving conditions.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.379-385
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• 2018

Purpose: Postharvest handling of onions (harvesting, cleaning, grading, cooling, storing, and transport) should be performed continually to reduce costs and improve quality. The purpose of this study is to a) determine the design parameters and operating conditions of anion auto-dumping that constitutes a key component of the postharvest bulk handling machinery system, and b) to perform a performance test with the auto-dump prototype system. Methods: Kinematic analyses and computer simulations of the auto-dump mechanism were applied to analyze the operating conditions and design parameters. Results: The optimum working condition for the auto-dump was determined from kinetic analyses. In addition, the interaction between the velocity of the hydraulic cylinder and the angular velocity of the auto-dump were analyzed in order to control the bulk handling machinery system. The acting forces and optimum operating conditions of the hydraulic cylinder were determined by analyzing the forces related to the mass of inertia of the auto-dump assembly during rotation. The method of controlling the feeding rate of onions in terms of the uniformity of the stacking pattern and the control of the entire system was better than the two-stage method of controlling the rotational speed of the auto-dump. Based on the performance test with the prototype for the auto-dump, the stacking pattern and rigidity of the system were analyzed. Conclusions: These results would be of great importance in the postharvest bulk handling machinery system for onions.

• Journal of applied mathematics & informatics
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• v.3 no.2
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• pp.129-148
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• 1996

This paper propose the inference mechanism for handling linear polynomial constraints called consistency checking algorithm based on the feasibility checking algorithm borrowed from linear pro-gramming. in contrast with other approaches proposed algorithm can efficiently and coherented by linear polynomial forms. The developed algorithm is successfully applied to the symbolic simulation that offers a convenient means to conduct multiple simultaneous exploration of model behaviors.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.527-537
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• 2016

Recent automakers are trying to be more precise with the dimension check and moving parts to guarantee high quality and satisfy customer requirements. The aim of this paper is to investigate the design tolerance suitability of door operating mechanism linked arms, lever, and cam-shaft in a mobile air handling unit. These parts are complicated because doors, arms, lever and cam-shaft are connected nonlinearly in 3D. The current tolerance analysis method poses problems in design analysis because the moving doors are reasonably suitable for the AHU function. The 3-DCS analysis method provided useful results not only in establishing the inspection criteria for the quality control of products but also in enabling economical production. As a result, the vent door had $1.62^{\circ}{\sim}1.72^{\circ}$ and the defrost door had $0.84^{\circ}{\sim}0.9^{\circ}$ for the directly connected arms operating-type. For the lever connected arm operating-type, the foot door had $2.0^{\circ}{\sim}2.24^{\circ}$ tolerance, while the tolerance values satisfied the air flow volume distribution rate criteria in the AHU. Finally, the results have confirmed the design's tolerance suitability by using 3-DCS analysis at the early design stages. Reliability can be achieved by analyzing accumulated tolerance during the sub-parts assembly process and the moving mechanism linked especially by arms, lever, and cam-shaft.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4774-4796
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• 2018

Wireless sensor networks are composed of a large number of inexpensive and tiny sensors used in different areas including military, industry, agriculture, space, and environment. Fault tolerance, which is considered a challenging task in these networks, is defined as the ability of the system to offer an appropriate level of functionality in the event of failures. The present study proposed an intelligent throughput descent and distributed energy-efficient mechanism in order to improve fault tolerance of the system against soft and permanent faults. This mechanism includes determining the intelligent neighborhood radius threshold, the intelligent neighborhood nodes number threshold, customizing the base paper algorithm for distributed systems, redefining the base paper scenarios for failure detection procedure to predict network behavior when running into soft and permanent faults, and some cases have been described for handling failure exception procedures. The experimental results from simulation indicate that the proposed mechanism was able to improve network throughput, fault detection accuracy, reliability, and network lifetime with respect to the base paper.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.973-976
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• 2005

In IEEE 802.15.4 (Low-Rate Wireless Personal Area Network) specification, a successful reception and validation of a data or MAC command frame can be confirmed with an acknowledgment. However, the specification does not support security for acknowledgment frame; the lack of a MAC covering acknowledgments allows an adversary to forge an acknowledgment for any frame. This paper proposes an identity authentication mechanism at the link layer for acknowledgment frame in IEEE 802.15.4 network. With the proposed mechanism there is only three bits for authentication, which can greatly reduce overhead. The encrypted bit stream for identity authentication will be transmitted to device by coordinator within association process. Statistical method indicates that our mechanism is successful in handling MAC layer attack.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.40-44
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• 2005

Recently PZT is used in ultra precision mechanism field. PZT itself has a small driving range although it has a high resolution. Many methods, such as inchworm, impact driving, inertial sliding method, etc., have been applied for moving range expansion. In this study, a new actuating mechanism for rotational motion with two driving PZT is proposed. The Fixed-Fixed beam support is applied for compensation of the difference in driving force between expansion and contraction of PZT. The behavior and design parameters of the proposed mechanism are analyzed for improving performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.121-125
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• 2003

A switch box is metal box for electric wire pipes in building. In manufacturing this box, the first press is used to mold and the second to fifth presses are used to process four-sides of a box. So four presses, four molds and four workers are needed. This leads to raise the manufacturing cost including machine lease rent, molding fee, and wages. To make matters worse, the roaring sound, vibration, and dangers of safety accidents make employees avoid from working that job. To solve this problem, a new Handling Mechanism and a cam die which combined four-die-involving processes into one die process were developed. That results job automation of the Job with one press and one die. The job avoidance problem is solved and manufacturing cost is reduced as well.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.58-64
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• 2024

The ability of the robot gripper to handle a wide range of objects significantly impacts its operational effectiveness. Among the robot grippers commonly used, the economically feasible choice is the relatively simple structure of a parallel gripper. To perform more densely packed tasks with a parallel gripper, it should be capable of handling small objects. Therefore, this study designs a parallel gripper mechanism equipped with assisting grippers to ensure smooth grasping of small objects. The parallel gripper is designed using a rack and pinion gear system, with two additional grippers on both side, and these assisting grippers are designed to be detachable. The two assisting grippers have different type of tip to grasp thin fabric shapes and thin stick shapes. The gripper prototype is used to verify the grasping capabilities for shapes achievable with a conventional parallel gripper and those intended for grasping with the assisting grippers through grasping experiments. Consequently, by equipping a conventional parallel gripper with assisting grippers as in this study, it becomes capable of handling a broader range of objects, in addition to its existing functionality.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3753-3761
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• 2000

There exist several versions of schema and instances created under different versions of the schema concurrently in the database in schema evolution environments. This paper proposes a mechanism for accessing instances regardless of versions in schema evolution environments in object relational databases. Access handling routines are used in accessing to the instances through the undefined attributes in the versions in which they were created. The change of semantic information of attributes is supported. Access handling routines are defined for each pair of semantics rather than defining backdate/update functions for each pair of versions of a class. A query language that accommodates version and semantic information is defined through the extension of the primitive SQL format.