• Korean Journal of Computational Design and Engineering
• /
• v.4 no.2
• /
• pp.110-120
• /
• 1999

In general, turbine blades are usually machined on 5-axis NC machine. The 5-axis machining of sculptured surface offers many advantages over 3-axis machining including the faster material-removal rates and an improved surface finish. But it is difficult and time-consuming to generated interference-free 5-axis tool path. This paper describes research on the algorithm for generation of an interference-free 5-axis NC data for machining turbine blades. The approach, using the section profile derived from the intersection of cutting planes with a triangulated-surface approximation, includes (1) CL-data generation by detecting an interference-free heel angle (2) the calculation method for finding a adaptive feed-rate value, and (3) the inverse kinematics depending on the structure of 5-axis machine.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.708-713
• /
• 1997

A remote data communication system for monitoring of NC machine fault diagnosis and status is developed. This system communicates with host PC by using dial-up communication method on PSTN. The developed system consists of (1)remote communication module among NC's and host PC using PSTN, (2) 8 channels analog data sensing module, (3) digital I/O module for control of NC machine, (4) communication module between NC machine and remote data communication system using RS-232c, and (5) Software man-machine interface. This system may be applied for remote sensing of the status in Fms. To show the veridity of the developed system, several examples are illustrated.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.5
• /
• pp.1092-1096
• /
• 1988

This paper presents a research on the development of a system which manages be tool data for the factory using NC machines. The tool information concerning each production stages of the industry is studied in the CIM(Computer Integrated Manufacturing) view point. The system gives the characteristics of the easy and reliable processing of the tool data by the help of menu and graphic functions. The DBMS(Data Base Management System) having relational model is used for the system build-up and is interfaced with CAD system for display of the tool geometry.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.12 no.2
• /
• pp.53-58
• /
• 2003

It is very important to measure linear cycle plane positioning accuracy of NC lathe as it effects all other parts of machines machined by them in industries. If the plane positioning accuracy of NC lathe is bad, the dimension accuracy and the change-ability of works will be bad in the assembly of machine parts. In this paper, computer software systems are organized to measure linear cycle plane positioning displacement of ATC(Automatic tool changer) on zx plane of NC lathe using two linear scales. And each sets of error data obtained from the test is descriptions to plots and the results of linear cycle plane positioning errors are expressed as nutriments by computer treatment.

• Journal of Gastric Cancer
• /
• v.21 no.4
• /
• pp.368-378
• /
• 2021

Purpose: When patients with early gastric cancer (EGC) undergo non-curative endoscopic submucosal dissection requiring gastrectomy (NC-ESD-RG), additional medical resources and expenses are required for surgery. To reduce this burden, predictive model for NC-ESD-RG is required. Materials and Methods: Data from 2,997 patients undergoing ESD for 3,127 forceps biopsy-proven differentiated-type EGCs (2,345 and 782 in training and validation sets, respectively) were reviewed. Using the training set, the logistic stepwise regression analysis determined the independent predictors of NC-ESD-RG (NC-ESD other than cases with lateral resection margin involvement or piecemeal resection as the only non-curative factor). Using these predictors, a risk-scoring system for predicting NC-ESD-RG was developed. Performance of the predictive model was examined internally with the validation set. Results: Rate of NC-ESD-RG was 17.3%. Independent pre-ESD predictors for NC-ESD-RG included moderately differentiated or papillary EGC, large tumor size, proximal tumor location, lesion at greater curvature, elevated or depressed morphology, and presence of ulcers. A risk-score was assigned to each predictor of NC-ESD-RG. The area under the receiver operating characteristic curve for predicting NC-ESD-RG was 0.672 in both training and validation sets. A risk-score of 5 points was the optimal cut-off value for predicting NC-ESD-RG, and the overall accuracy was 72.7%. As the total risk score increased, the predicted risk for NC-ESD-RG increased from 3.8% to 72.6%. Conclusions: We developed and validated a risk-scoring system for predicting NC-ESD-RG based on pre-ESD variables. Our risk-scoring system can facilitate informed consent and decision-making for preoperative treatment selection between ESD and surgery in patients with EGC.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.3
• /
• pp.1298-1310
• /
• 2019

Network coding (NC) is a promising technology that can improve available bandwidth and packet throughput in wireless sensor networks (WSNs). Sliding window is an improved technology of NC, which is a supplement of TCP/IP technology and can improve data throughput and network lifetime on WSNs. This paper proposes a network coding-based maximum lifetime algorithm for sliding window in WSNs (NC-MLSW) which improves the throughput and network lifetime in WSN. The packets on the source node are sent on the WSNs. The intermediate node encodes the received original packet and forwards the newly encoded packet to the next node. Finally, the destination node decodes the received encoded data packet and recovers the original packet. The performance of the NC-MLSW algorithm is studied using NS2 simulation software and the network packet throughput, network lifetime and data packet loss rate were evaluated. The simulations experiment results show that the NC-MLSW algorithm can obviously improve the network packet throughput and network lifetime.

• ETRI Journal
• /
• v.43 no.1
• /
• pp.7-16
• /
• 2021

Noncontiguous orthogonal frequency division multiplexing (NC-OFDM)-based cognitive radio (CR) systems achieve highly efficient spectrum utilization by transmitting unlicensed users' data on subcarriers of licensed users' data when they are free. However, there are two disadvantages to the NC-OFDM system: out-of-band power (OBP) and a high peak-to-average power ratio (PAPR). OBP arises due to side lobes of an NC-OFDM signal in the frequency domain, and it interferes with the spectrum for unlicensed users. A high PAPR occurs due to the inverse fast Fourier transform (IFFT) block used in an NC-OFDM system, and it induces nonlinear effects in power amplifiers. In this study, we propose an algorithm called "Alternative Projections onto Convex and Non-Convex Sets" that reduces the OBP and PAPR simultaneously. The alternate projections are performed onto these sets to form an iteration, and it converges to the specified limits of in-band-power, peak amplitude, and OBP. Furthermore, simulations show that the bit error rate performance is not degraded while reducing OBP and PAPR.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1992.04a
• /
• pp.317-322
• /
• 1992

Developed in this reseach is a CAM system for 5-axis NC Machining of sculpture surfaces. We identify problems in generating 5-axis NC data and propose methods of overcoming them. Issues discussed in this report are; kinematic modelling of NC machines; Determination of cutter position(location and orientation); check of machine work-range; linear trajectory planning; calculation of feedrate number. The proposed system has been implemented in FORTRAN77 on the Personal IRIS EWS, and it also consitutes a module of the CAD/CAM system 'CASSETTE' developed in KIST CAD/CAM lab..

• Journal of the Korean Society for Precision Engineering
• /
• v.10 no.1
• /
• pp.108-113
• /
• 1993

This paper proposes a method for obtaining blend surfaces between machining data of surfaces. This blending algorithm consists of trangation, detection, tracing, construction of blend surfaces, and generation of machining data for the blend surfaces. Inpus of the algorithm are a blend radius and machining data of surfaces to be blended. CL data as well as CC data can be applied as an input machining data of the algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.05a
• /
• pp.257-264
• /
• 2004

분산 제조 시스템간의 협업을 가능케 하는 e-Manufacturing paradigm 의 성공을 위해서는 CAD-CAM-CNC chain 의 제조 분야뿐만 아니라 SCM, ERP, CRM 등의 상위 시스템과의 제품 및 가공 정보의 원활한 흐름이 필수적이다. STEP 과 STEP-NC 는 이를 해결할 표준으로 자리매김 할 것으로 기대되고 있다. 본 논문은 STEP-NC 의 국내 promotion 차원에서 참고문헌 [1]의 밀링용 파트프로그래밍 소개에 이어: 1) 선반용 데이터 모델, 2) 선반용 파트 프로그램의 작성 방법, 3) XML 을 이용한 파트 프로그램의 표현 방법들을 소개하고, 4) STEP-NC 기반의 생산 환경 구축을 위한 방안을 기술하였다.