• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.107-112
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• 2015

Increased productivity and cost reduction have emerged as the main goals of the industry due to the development of the machinery industry, and mechanical materials with excellent properties with the development of the machine tool industry are widely used in machine parts or structures. In addition, the cutting process of production plays a pivotal role in the production technology. Studies on cutting have involved a lot of research on the material, the cutting tool, the processing conditions, and numerical analysis. Due to the development of the computer through numerical analysis, cutting conditions, the assessment of cutting performance, and cutting quality could be predicted. This research uses the creation of the material model and AdvantEdge Production module for the NC code analysis. To improve the productivity, this research employs the optimization method to reduce cutting time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.547-552
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• 2003

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR (material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over 300m. so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL(cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants wire applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to speaker mold machining. The finishing time was reduced to 12.6%. tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were removed.

• International journal of advanced smart convergence
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• v.2 no.1
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• pp.6-11
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• 2013

Network Coding (NC) is a new paradigm for network communication. In network coding, intermediate nodes create new packets by algebraically combining ingress packets and send it to its neighbor node by broadcast manner. NC has rapidly emerged as a major research area in information theory due to its wide applicability to communication through real networks. Network coding is expected to improve throughput and channel efficiency in the wireless multi-hop network. Many researches have been carried out to employ network coding to wireless ad-hoc network. In this paper, we proposed a dynamic queue management to improve coding opportunistic to enhance efficiency of NC. In our design, intermediate nodes are buffering incoming packets to encode queue. We expect that the proposed algorithm shall improve encoding rate of network coded packet and also reduce end to end latency. From the simulation, the proposed algorithm achieved better performance in terms of coding gain and packet delivery rate than static queue management scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.6
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• pp.1668-1688
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• 2012

Cooperative communications and network coding schemes have been proposed to increase system throughput for ad hoc networks. In this paper, we present throughput and delay analysis of the new network coding-enabled cooperative MAC protocol called NC-MAC, which has been proposed by us in order to significantly enhance system performance. This protocol introduces an approach that can accommodate both cooperative communication and network coding for wireless ad hoc networks by slightly increasing overhead and modifying standards. The protocol's performance is evaluated using mathematical analysis and computer simulation and two performance measures, system throughput and average channel access delay, are used for a performance comparison with previous schemes. It is assumed that all the frames exchanged over a wireless channel are susceptible to transmission errors, which is a new but more reasonable assumption differentiating this research from previous research. Numerical results show this protocol provides significantly enhanced system performance compared with conventional cooperative MAC protocols used in previous research. For instance, system performance is 47% higher using the NC-MAC protocol than when using the rDCF protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4205-4227
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• 2018

Network Coding (NC) is an approach recently investigated for increasing the network throughput and thus enhancing the performance of wireless mesh networks. The benefits of NC can further be improved when routing decisions are made with the awareness of coding capabilities and opportunities. Typically, the goal of such routing is to find and exploit routes with new coding opportunities and thus further increase the network throughput. As shown in this paper, in case of proactive routing the coding awareness along with the information of the measured traffic coding success can also be efficiently used to support the congestion avoidance and enable more encoded packets, thus indirectly further increasing the network throughput. To this end, a new proactive routing procedure called Congestion-Avoidance Network Coding-Aware Routing (CANCAR) is proposed. It detects the currently most highly-loaded node and prevents it from saturation by diverting some of the least coded traffic flows to alternative routes, thus achieving even higher coding gain by the remaining well-coded traffic flows on the node. The simulation results confirm that the proposed proactive routing procedure combined with the well-known COPE NC avoids network congestion and provides higher coding gains, thus achieving significantly higher throughput and enabling higher traffic loads both in a representative regular network topology as well as in two synthetically generated random network topologies.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.9-15
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• 2011

In order to develop a practical postprocessor for 5-axis machining, the general equations of numerically controlled (NC) data for 5-axis configurations with not only non-orthogonal rotary axes but also orthogonal rotary axes were exactly expressed by the inverse kinematics, and a Windows-based postprocessor written in Visual Basic was developed according to the proposed algorithm. The developed postprocessor is a general system that suitable for all kinds of 5-axis machine tool with orthogonal and non-orthogonal rotary axes. Through implementation of the developed postprocessor and verification by a cutting simulation and machining experiment, the effectiveness of the proposed algorithm is confirmed. Compatibility is improved by allowing exchange of data formats such as rotational tool center position (RTCP) controlled NC data, vector post NC data, and program object file (POF) cutter location (CL)data, and convenience is increased by adding the function of work-piece origin offset. Consequently, the technology of practical post-processor for 5-axis machining is developed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.9
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• pp.700-706
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• 2013

In this paper, we propose a method for applying random linear network coding in satellite communication to improve reliability. In the proposed protocol, network-coded redundancy (NC-R) packets are transmitted in the PEP (Performance Enhancement Proxy). Therefore, if data packets is lost by wireless channel error, they can be recovered by NC-R packets. We also develop the TCP performance model of the proposed protocol and evaluate the performance of the proposed protocol. In the simulation results, It is shown that the proposed protocol can improve the TCP throughput as compared with that of the conventional TCP because the NC-R packets is sent by the sender-side PEP and the receiver-side PEP use these packets to recover the lost packets, resulting in reducing the packet loss in TCP.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.149-154
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• 1996

The applicability of a new method, termed the whirling motion concept, for the iprovement of the surface finish in milling three-dimensional sculptured surfaces has been investigated. A method for implementing this concept on conventional NC machines that utilize a suitably configured attachment has been proposed. The tool path equation for the ball-end milling process, based on the Surface-Shaping system, has been obtained. Both results of the computer simulation and the experiment verified the computer simulation and the experiment verified the proposed approach.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.200-205
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• 1988

The paper introduces the system AUTO-CUT for the automatic generation of NC tapes for wire-cut EDM(Electrodischarge Machining) parts. The information input to the system is the description of the part geometries, the tool motions and the cutting conditions etc. The system generates CLDATA and machine control data. Also dynamic simulation of tool motions can be performed on the screen.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.698-706
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• 2005

Finish machining of a curved surface is often carried out by an NC system with curve interpolation in the field. This NURBS interpolation adopts a feedrate optimizing strategy based on both the geometrical information and dynamic properties. In case of a finish cut using a ball-end mill, the curve interpolator needs to take the machining process into account for more improved surface, while reducing the polishing time. In this study, the effect of low machinability at the bottom of a tool on surface roughness is also considered. A particular curve interpolation algorithm is proposed fur generating feedrate commands which are able to control the roughness of a curved surface. The simulation of the machined surface by the proposed algorithm was carried out, and experimental results are presented.