• Proceedings of the KSR Conference
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• 2004.10a
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• pp.793-799
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• 2004

In track a third weakness point is joint part, turnout part, curve part. One of them joint part of rail have been known to the most weak point by loosen of joint bar and fish bolt due to impulse and vibration by wheel contact at times. In addition happen to deformation and failure at end of rail, failure and miniature of ballast gravel. Finally impact between wheel and rail become origin cause of a welded rail, noise and vibration. riding condition deterioration, besides track failure. In the present domestic, Thermite and Gas pressure weldings have been used to continuous welded rail(CWR), however stiffness and confidence in quality is lower than Flash butt welding method. FRW have the excellent capacity, however have a shortcoming large scale of machine and power equipment. Therefore we will introduce Mobile Flash Butt Welder can weld in track.

• Journal of Construction Engineering and Project Management
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• v.1 no.2
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• pp.18-27
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• 2011

Egyptian construction firms (ECF) started recently to adopt quality management system (QMS) as a way to develop and improve their performance as previous studies have shown. However, considering all the firm's aspects in a competitive way is a crucial process for the ECF's culture. This research is trying to indicate the role of the QMS implementation in measuring performance (MP) through developing a model for measuring performance at the organizational level, and to explore its impact on the organizations that adopt QMS. This model is based on specific elements and their related indicators which have been derived from national approaches and models of MP. This model determines the performance level (PL) of the organization that is measured by means of a point system. Weights of the elements in the point system considered both the elements' importance in the international models and its real practice in the ECFs. This model has been validated using another questionnaire and the majority of surveyed experts agreed that the proposed model can be applied effectively.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.1
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• pp.47-53
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• 1992

This paper is discussing the Optimum Structural Modification by the Sensitive Analysis Method. The mokificxation for the first Mouth Open Mode of the C type structure was done by using coordinate sensitivities and thickness sensitivities. The results obtained are as follows; 1. the vibration could be minimized by reducing multiples of mode components of impact point and response point. 2. the tooling precision of the Press machine could be minimized by reducing relative vibration amplititutes between the tool and the object to be tooled. 3. the mode componets of 2 points could be identified by using the coordinate sensitivites for the C type structure. 4. the mode components of 2 points could be iodentified by using the thickness sensitivities for the C type structure.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.973-980
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• 2024

Dependence of dynamic fracture path on loading velocity was observed from experimental results based on the three point bending fracture in cast iron. In this study, 3D and 2D numerical simulations are used to evaluate singular stress fields near crack tip and fracture mechanics parameters. Moving finite element technique, 2D and 3D Delauney automatic mesh generation and contact-noncontact evaluation is introduced into the numerical method. Dynamic fracture thoughness is decreased with increase of impact loading velocity. Fracture mode-ratio corresponds to initial kink angle of fracture path. The numerical result shows that the maximum hoop stress criterion cannot be applied to dynamic fracture of cast iron.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.555-558
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• 2003

This study carried out to analyze the characteristics of water concentration for Saemangeum reclaiming area during two seasons. Total nitrogen appeared by thing which all mean values are the biggest at two survey at ST.4 that is near with Mangyoung river. At the same time, change by range of tide was seen. Therefore, is thought that ST.4 suffers impact of river and seawater at the same time. But is thought that water of Mangyoung river exerts bigger effect than seawater because ST.4 appears that concentration is high clearly with different Sampling point. Therefore, is thought that pollution occurs better than different sampling point if ST.4's flowing deters.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.231-235
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• 2013

Lens distortions have a significant impact on captured or projected image geometry. This paper proposes a lens distortion correction with gradient components for wide-angle lenses. In most cases, distortion coefficients are estimated using a distortion model by point correspondences. Corrected images using only point correspondences can be compensated excessively, therefore, producing bended lines into the opposite direction near the corners. To curtail these phenomena, we propose to adopt the gradient components in addition to positions to obtain the distortion coefficients. We verified the improved accuracy and the straightness of the proposed method through experimentation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.47-52
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• 2008

The force transducer in the acceleration plant due to dynamic fracture is calibrated by dynamically using the stress pulses from a longitudinal bar. The bar is supported by two strings attached to the ceiling. The bar velocities before and after impact are measured and a full bridge at bar and transducer is formed by the four strain gauges. A transient recorder is used to store the stress pulse signals of force transducer and bar. For the first test series, three point bend test specimens can be chosen by means of test rig design and the inspection as sample experiment in this presented paper is sufficient for proving with the numerical simulation of the specimen model.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.3
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• pp.176-187
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• 2013

Message replay, malicious Access Point (AP) associations and Denial of Service (DoS) attacks are the major threats in Wireless LANs. These threats are possible due to a lack of proper authentication and insecure message communications between wireless devices. Current wireless authentication & key exchange (AKE) schemes and security protocols (WEP, WPA and IEEE 802.11i) are not sufficient against these threats. This paper presents a novel Secure WLAN Authentication Scheme (SWAS). The scheme introduces the delegation concept of mobile authentication in WLANs, and provides mutual authentication to all parties (Wireless Station, Access Point and Authentication Server). The messages involved in the process serve both authentication and key refreshing purposes. The scheme enhances the security by protecting the messages through cryptographic techniques and reduces the DoS impact. The results showed that cryptographic techniques do not result in extra latencies in authentication. The scheme also reduces the communication cost and network overhead.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1089-1092
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• 2001

In order to measure the vibration of a ribbed clindrical shell, the principle of reciprocity has been implemented. An accelerometer was fixed at the position defined as the excitation point. An impact hammer was used to tap at the response array points (64 points) located along the circumference of the shell. The frequency response function was reciprocally measured at each point in turn. The response data was processed to obtain the frequency/wavenumber spectrum. From the spectrum the characteristics of wave propagation on the ribbed cylindrical shell have been observed.

• Journal of Ocean Engineering and Technology
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• v.38 no.3
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• pp.115-123
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• 2024

USBL systems are essential for providing accurate positions of autonomous underwater vehicles (AUVs). On the other hand, the accuracy can be degraded by outliers because of the environmental conditions. A failure to address these outliers can significantly impact the reliability of underwater localization and navigation systems. This paper proposes a novel outlier rejection algorithm for AUV localization using Voronoi diagrams and query point calculation. The Voronoi diagram divides data space into Voronoi cells that center on ultra-short baseline (USBL) data, and the calculated query point determines if the corresponding USBL data is an inlier. This study conducted experiments acquiring GPS and USBL data simultaneously and optimized the algorithm empirically based on the acquired data. In addition, the proposed method was applied to a sensor fusion algorithm to verify its effectiveness, resulting in improved pose estimations. The proposed method can be applied to various sensor fusion algorithms as a preprocess and could be used for outlier rejection for other 2D-based location sensors.