• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.6
• /
• pp.79-89
• /
• 1998

In determining optimal cutting condition for face milling operation, tool wear is an important factor. For the purpose of establishing the relationship between various machining factors and tool wear, cutting tests have been performed. As a result, hardness and chemical composition of workpiece material, chemical composition and grain size of cutting tool and cutting speed have been selected as machining factors. In addition, relationship between feed rate and workpiece hardness has been observed. Prior to utilizing cutting conditions recommended by ‘Machining Data Handbook(MDH)’ as a knowledge base, an analysis for the validity of the MDH has been provided. Based on this analysis, tool life criteria applied by MDH has been modified. Finally, using MDH recommended data for neural network trainning, the results from the trained neural network for optimal cutting condition for some given workpiece and cutting tool can be used as reference cutting conditions.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.5
• /
• pp.882-889
• /
• 2010

This paper presents a method of finding the optimal operating point minimizing a given objective function with 3 phase power flow equations and operational constraints, called 3 phase optimal power flow (3POPF). 3 phase optimal power flow can provide operation and control strategies for the distribution systems with distributed generation assets, which might be frequently in unbalanced conditions assuming that high penetration rate of renewable energy sources in the systems. As the solution technique for 3POPF, this paper adopts a simulation-based method of particle swarm optimization (PSO). In the PSO based 3POPF, a utility function needs to be defined for evaluation of the degree in operational improvement of each particle's current position. To evaluate the utility function, in this paper, NR-based 3 phase power flow algorithm was developed which can deal with looped distributed generation systems. In this paper, illustrative examples with a 5-bus and a modified IEEE 37-bus test systems are given.

• Food Science and Biotechnology
• /
• v.14 no.3
• /
• pp.380-386
• /
• 2005

Optimal conditions of ultrafiltration (UF) and nanofiltration (NF) were investigated for separation and concentration of isoflavones and oligosaccharides from Sunmul. Levels of COD, BOD, and suspended solids (SS) in UF and NF permeates were also determined to evaluate effectiveness of these processes for reducing water pollution. Optimal UF operation conditions to achieve minimal fouling and maximal flux were $33-34^{\circ}C$ operating temperature and 2.3-2.4 bar trans-membrane pressure. Recovery yields of isoflavones and oligosaccharides in UF retentate were 11.49-28.16% and 12.77-27.57%, respectively. Increase in volumetric concentration factor (VCF) resulted in more functional compounds of isoflavones and oligosaccharides passing through UF membrane. Total isoflavone and oligosaccharide yields decreased by 3% as VCF increased from 6.0 to 8.0 and from 8.0 to 10.0, while decreased significantly by 10% as VCF decreased from 4.0 to 6.0. Optimal NF operating conditions were 192-195 psig operating pressure at $30-33^{\circ}C$. Total yields of isoflavones and oligosaccharides significantly decreased at VCF 8.0, whereas did not decrease up to VCF 6.0 during NF operation. Therefore, VCF 6.0 was recommended for economical process. COD and BOD decreased by more than 98% after NF process, and SS were not detected after UF process. These results indicated sequential filtration process was useful for separation of isoflavones and oligosaccharides from Sunmul and for reducing water contaminants.

• Korean Chemical Engineering Research
• /
• v.46 no.1
• /
• pp.147-155
• /
• 2008

The economics of most chemical plants are heavily dependent upon the management of the utilities used in the plants. The utilities are supplied by the centralized utility system of the plant. Among the various utilities the steam is by far the most important energy source and the management of the electricity and the process water are greatly affected by the steam. Therefore it is necessary to educate students and new employees the basic concepts about the effective distribution of the utilities and the fundamental strategies to apply the concepts in actual plant operations. The OOUS (Optimal Operation of Utility System) is an GUI educational system designed to educate the effective generation of the steam and the optimal steam distribution schemes within short period. The OOUS deals with various utility equipments and processes and shows how to save operation costs by displaying the optimal operation conditions based on the process models and the operational knowledgebase.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.9
• /
• pp.1152-1158
• /
• 2018

In this paper, Optimal operation plan through load analysis of industrial end-user is suggested. It calculated economic feasibility of ESS with detailed power lad analysis and conditions. Generally, if the latest maximum power is less than 30% of contracted power, it can not be peak shaving operation plan. and if the peak load level stays stead for 24 hours, it is difficult peak shaving for ESS. In addition to, When the peak load is occurred in summer or winter, a hybrid operation method combining the peak shaving plan and the time shift method is proposed. Therefore, When ESS is installed in industrial electrical customer, it is achieved best effect through the optimal operation plan.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2016.05a
• /
• pp.62-63
• /
• 2016

Existing studies relative to enhancing sustainability of earth-work are mainly involved in the performance of construction equipments. They assume that there is no variation of the engine power and fuel consumption and classify the dozer operation into working and idle conditions. They enable to find the most eco-friendly equipment fleet deployment plan. However, they are confined in that they do not provide a measure to assess the sustainability of the operation plan and suggest optimal alternative(s). This paper presents a method that identifies an optimal dozer operation plan that assures sustainability by reducing fuel consumption of the equipment. The method computes the dozer operation productivity using engine-torque-output map provided by equipment manufacturers. Indeed, it identifies the eco-dozing operation that minimizes fuel consumption and maximizes the target productivity.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.12
• /
• pp.1582-1590
• /
• 2004

The purpose of this study is to show the existence of optimal operation conditions for minimum fuel consumption of the gas turbine based combined cycle cogeneration power plant. Optimal operational condition means the optimal distribution of the power generated by each gas turbine and the heat generated by each HRSG. Total fuel consumption is calculated by the sum of the fuels for gas turbines and supplementary boiler. Fuel consumption is calculated by numerical methods of energy equations which contain the power generated from gas and steam turbines, the heat generated by HRSG and the heat extracted from high pressure steam turbine.

• Journal of IKEEE
• /
• v.13 no.2
• /
• pp.175-180
• /
• 2009

This paper compare the operation characteristic and optimal design of Photovoltaic system by computer simulation. The operation characteristic of Photovoltaic system are evaluated and analyzed considering system parameters of specifications, installations, inclination, azimuth and surrounding conditions etc. From the basis of these results, this study will intend to develop an evaluation, analysis tool and construct database for optimal design of PV system.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.482_483
• /
• 2009

This paper presents a method of finding the optimal operating point minimizing a given objective function with 3 phase power flow equations and operational constraints, called 3 phase optimal power flow. 3 phase optimal power flow can provide operation and control strategies for the distribution systems with distributed generation assets, which might be frequently in unbalanced conditions assuming that high penetration rate of renewable energy sources in the systems. As the solution technique, this paper adopts a standard particle swarm optimization (PSO).

• Korean Chemical Engineering Research
• /
• v.45 no.3
• /
• pp.234-241
• /
• 2007

To achieve safe operation and to improve economics it is imperative to monitor and analyse demand and supply of utilities and to meet utility needs in time. The main objective of motor/turbine processes is to manipulate steam and electricity balances in utility plants. The optimal operation of motor/turbine processes is by far the most important to improve economics in the utility plant. In order to analyse motor/turbine processes, we need steady state models for steam generation equipments and steam distribution devices as well as turbine generators. In addition heuristics concerning various operational situations are required. The motor/turbine optimal operation system is based on utility models and operational knowledgebase and provides optimal operating conditions when the amount of steam demand from various steam headers is changed frequently. The optimal operation system also produces optimal selection of driving devices for utility pumps to reduce operating cost.