• Proceedings of the KSR Conference
• /
• 2003.10c
• /
• pp.151-156
• /
• 2003

The Communication Based Train Control(CBTC) System generally used to improving existing lines in the world is efficient and stable for improvement. Also it is efficient for improvement because it does not cause any problems in operation of existing lines. We examined the mixed operation scheme for more efficient and stable improvement when improvement is implemented depending on aged equipment and the increased number of passengers in the Korean city railroad. The biggest point in the mixed operation is to implement a stable test without interfering with the operation of the existing lines. For this purpose, we deduced a method of installing the equipment, a method of testing depending on the installed equipment, and the types of mixed operation, and presented a scheme of execution of the methods depending on the mixed operation.

• The Journal of Information Technology
• /
• v.4 no.4
• /
• pp.51-63
• /
• 2001

Residue Number System has carry free operation and parallelism each modulus, So it is used for special purpose processor such as Digital Signal Processing and Neuron Processor. Magnitude comparison and sign detection are in need of Mixed Radix Conversion, and these operations are impediment to improve the operation speed. So in this Paper, MRC(Mixed Radix Converter) is designed using modified partitioned residue to speed up the operation of MRC, so it has progressed maximum twice operation time but increased the size of converter comparison to other converter.

• Journal of Korean Institute of Industrial Engineers
• /
• v.30 no.4
• /
• pp.346-354
• /
• 2004

Most industrial logistic systems have focused on carrying products from manufacturers or distribution centers to customers. In recent years, they are faced with the problem of integrating reverse flows into their transportation systems. In this paper, we address the vehicle routing problems with mixed delivery and pick-up(VRPMDP). Mixed operation of delivery and pick-up during a vehicle tour requires rearrangement of the goods on board. The VRPMDP considers the reshuffling time of goods at customers, hard time windows, and split operation of delivery and pick-up. We construct a mixed integer mathematical model and propose a new genetic algorithm named GAMP for VRPMDP. Computational experiments on various types of test problems are performed to evaluate GAMP against the modified Dethloff's algorithm. The results show that GAMP reduces the total vehicle operation time by 5.9% on average, but takes about six times longer computation time.

• Journal of Environmental Health Sciences
• /
• v.20 no.4
• /
• pp.10-16
• /
• 1994

A Study was performed in order to measure mixed organic solvent concentrations in air of painting operations during January 5-28, 1991. The mixed organic solvent concentrations were analyzed by the gas chromatography. The results were as follows: 1. The detection of organic solvent was highest in aromatic hydrocarbon(68%), and followed by aliphatic hydrocarbon (18%), and ketone (14%). 2. The detection of organic solvent by component category was highest in the grid class solvent (79.4%), and followed by the 3rd class solvent (20.6%). 3. Number of cases exceeding TLVS of mixed solvent level in air was highest on dipping operation (44%), and followed by spray operation (40%), dry and washing operation (33%), and adhensive operation (12%).

• Journal of the Korean Operations Research and Management Science Society
• /
• v.30 no.2
• /
• pp.143-156
• /
• 2005

Facility location planning (FLP) problem is the strategic level planning in supply chain. The FLP is significantly affected by the operation time of each facility. In most of the FLP researches, operation time of facility has been treated as a fixed value. However, the operation time is not a static factor in real situations and the fixed operation time may lead unrealistic FLP. In this paper, a mixed integer programming (MIP) model is proposed for solving the 3-stage FLP problem and operation times are adjusted by the results from the simulation model and an iterative approach combining the analytic model and simulation model is proposed to obtain more realistic operation plans for FLP problems.

• Journal of the Korean School Mathematics Society
• /
• v.20 no.2
• /
• pp.141-161
• /
• 2017

As it's important to understand the order of operation in the mixed calculation of natural number and perform it, mathematics curriculums and textbooks focused that students can calculate with understanding the order of operation and its principles. For attaining the implications of teaching about the mixed calculations, this study analyzed the problem solving abilities and error types of 67 elementary students and 57 pre-service teachers using questionnaire which was developed in this study and composed of numeric expressions and word problems. The conclusions drawn from this study were as follows: Students were revealed the correct rates(86.2% and 73.5%) in numeric expressions and word problems, but they were showed the paradigmatic error types-the errors of the order of operation and the composition of numeric expression from word problems. Even though the correct rates of the preservice teachers were extremely high, the result of problem solving processes required that it's needed to be interested in teaching the principles of the order of operation in the mixed calculations. In addition, subjects were revealed the problems about using parentheses and equal sign.

• Membrane and Water Treatment
• /
• v.7 no.4
• /
• pp.367-375
• /
• 2016

Although the bucky paper (BP) made from carbon nanotubes (CNTs) possesses beneficial characteristics of hydrophobic nature and high porosity for membrane distillation (MD) application, weak mechanical strength of BP has often prevented the stable operation. This study aims to fabricate the BP with high mechanical strength to improve its MD performance. The strategy was to increase the purity level of CNTs with an assumption that purer CNTs would increase the Van der Waals attraction, leading to the improvement of mechanical strength of BP. According to this study results, the purification of CNT does not necessarily enhance the mechanical strength of BP. The BP made from purer CNTs demonstrated a high flux ($142kg/m^2{\cdot}h$) even at low ${\Delta}T$ ($50^{\circ}C$ and $20^{\circ}C$) during the experiments of direct contact membrane distillation (DCMD). However, the operation was not stable because a crack quickly formed. Then, a support layer of AAO (anodic aluminum oxide) filter paper was introduced to reinforce the mechanical strength of BP. The support reinforcement was able to increase the mechanical strength, but wetting occurred. Therefore, the mixed matrix membrane (PSf-CNT) using CNTs as filler to polysulphone was fabricated. The DCMD operation with the PSf-CNT membrane was stable, although the flux was low ($6.1kg/m^2{\cdot}h$). This result suggests that the mixed matrix membrane could be more beneficial for the stable DCMD operation than the BP.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.11
• /
• pp.1610-1616
• /
• 2013

Recently, district heating and cooling (DHC) systems based on combined cycle generation (CCG) providers are increasing in Korea. Since characteristics of combined heat and power (CHP) generators and heat demands of providers, heat trading between DHC providers based on the economic viewpoint is required; the heat trading has been doing. In this paper, a mathematical model for optimal operation based on heat trading between DHC providers is proposed. Especially, start-up characteristic of CCG is included. The operation model is established by mixed integer linear programming (MILP).

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1996.05a
• /
• pp.197-205
• /
• 1996

A combined extrusion process studied here consists of forward and backward extrusion, and it is formed in single operation. The metal flow involved in the operation has appeared to be difficult to analyze accurately because of mixed directions of the flow. In this study, conventional two operations of a forward and a backward extrusions is transformed into one operation of mixed extrusion. A process designed by an industry expert is simulated by the rigid-plastic finite element method to investigate the metal flow and defects. In addition to the FEM simulation, experimental analysis has been carried out to confirm the design in industry, which includes material characterization, preliminary expriment, and whole experimental forming operation. The experimental results show that warm forming of extrusion is more desirable than cold working and hot forming in view of grain growth. Also two conditions of lubrication between workpiece and die has been investigated.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.245-248
• /
• 1997

The control modes used in teleoperation are position control mode, and rate control mode. This paper presents the problems of the conventional control modes, through simulation, proposes an intelligent mixed control mode that converts the operation mode between the position mode and the rate mode intelligently by judging the operator's intention using the real-time measurement data. The effectiveness of the proposed intelligent mixed control mode is demonstrated and compared to other typical control modes through simulation and actual experiment.