• Journal of Korean Institute of Industrial Engineers
• /
• v.32 no.4
• /
• pp.373-381
• /
• 2006

This paper considers a scheduling problem for a hybrid flowshop with dynamic order arrival. A hybrid flowshop is an extended form of a flowshop, which has serial stages like a flowshop but there can be more than one machine at each stage. In this paper, we propose a new method for the problem of scheduling with the objective of minimizing mean tardiness of orders which arrive at the shop dynamically. The proposed method is based on the list scheduling approach, however we use a more sophisticated method to prioritize lots unlike dispatching rule-based methods. To evaluate the performance of the proposed method, a simulation model of a hybrid flowshop-type production system is constructed. We implement well-known dispatching rules and the proposed methods in the simulation model. From a series of simulation tests, we show that the proposed methods perform better than other methods.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 1999.11a
• /
• pp.168-171
• /
• 1999

For the axial crushing tests of various shape of tubes, it was reported that composite tubes need trigger mechanism to avoid brittle failure. In this study, static axial crush tests were performed with the new aluminum/GFRP hybrid tubes. Glass/Epoxy prepregs were wrapped around aluminum tube and co-cured. The failure of hybrid tube was stable and progressive without trigger mechanism, and specific energy absorption was increased to maximum 34% in comparison with aluminum tube. Effective energy absorption is possible for inner aluminum tube because wrapped composite tube constrain the deflection of aluminum tube and reduce the folding length. The failure of hybrid composite tube was stable without trigger mechanism because inner aluminum tube could play the role of crack initiator and controller. Aluminum/Glass-Epoxy hybrid tube is suitable for the vehicle front structure due to effective energy absorption capability, easy production, and simple application for RTM process.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.5
• /
• pp.205-210
• /
• 2004

Sub-cooled hybrid condenser(SCHC) which have been developed through this study is an appliance of integrating a condenser with a receiver dryer, which were previously separated. It is supposed that the development of sub-cooled hybrid condenser will be able to reduce not only weight, size, production process and cost, but also quite improve in capability, which will be of great use for the technological development and research of an air conditioning system whose importance is higher in a car. Through the present study it was found that the developed SCHC increases in the degree of sub-cooling by 10∼100% compared to conventional condenser. The excessive sub-cool has improved the cooling performance by 10%, and that leads to the reduction in evaporator outlet air temperature $1.5^{\circ}C$. Additionally, it is expected that sub-cooled hybrid condenser weights less by 100g than the previous condensers which has equal super heat.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.12
• /
• pp.2202-2207
• /
• 2008

Bearingless SRM(Switched Reluctance Motor) is researched for high speed or special applications which can not use mechanical bearing such as bio pump. In this paper, a novel hybrid pole bearingless SRM is presented. The proposed hybrid pole bearingless SRM has salient poles for torque and suspending force production. Motor torque is controlled by the phase currents in torque pole windings, and the suspending force is controlled by suspending currents in four suspending windings for radial direction suspension. Because the proposed bearingless SRM has divided pole structure, mutual effects between torque current and suspending current are very lower than the conventional one's. From this structure, the number of power devices for power converter can be reduced for bearingless SRM driving. The proposed hybrid pole bearing less SRM is verified by the FEM analysis and experimental results.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.7 no.4
• /
• pp.770-783
• /
• 2015

Lately, high production rate welding processes for Al alloys, which are used as LNG FPSO cargo containment system material, have been developed to overcome the limit of installation and high rework rates. In particular, plasma-metal inert gas (MIG) hybrid (PMH) welding can be used to obtain a higher deposition rate and lower porosity, while facilitating a cleaning effect by preheating and post heating the wire and the base metal. However, an asymmetric undercut and a black-colored deposit are created on the surface of PMH weld in Al alloys. For controlling the surface defect formation, the wire feeding speed and nozzle diameter in the PMH weld was investigated through arc phenomena with high-speed imaging and metallurgical analysis.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.11
• /
• pp.2200-2208
• /
• 2009

This paper presents a novel single converter and single inverter (1Con-1Inv) topology for photovoltaic (PV)-fuel cell (FC) hybrid system and a new control scheme for the PV-FC hybrid system is then proposed. The new topology and the unique algorithm can minimize volume and production cost of the hybrid system. Moreover, system efficiency can improve due to reduction of losses of hardware components and other control factors are well regulated using just 1Con-1Inv with the help of the proposed control algorithm. The validity of proposed algorithm is verified both computer simulation using PSIM and Matlab/Simulink program and experimental with 700W of PV and 600W of FC system.

• Advances in Energy Research
• /
• v.5 no.2
• /
• pp.107-128
• /
• 2017

Energy is a major component of almost all economic, production, and service activities, and rapid population growth, urbanization and industrialization have led to ever growing demand for energy. Limited energy resources and increasingly evident environmental effects of fossil fuel consumption has led to a growing awareness about the importance of further use of renewable energy sources in the countries energy portfolio. Renewable hydrogen production is a convenient method for storage of unstable renewable energy sources such as wind and solar energy for use in other place or time. In this study, suitability of 25 cities located in Iran's western region for renewable hydrogen production are evaluated by multi-criteria decision making techniques including TOPSIS, VIKOR, ELECTRE, SAW, Fuzzy TOPSIS, and also hybrid ranking techniques. The choice of suitable location for the centralized renewable hydrogen production is associated with various technical, economic, social, geographic, and political criteria. This paper describes the criteria affecting the hydrogen production potential in the study region. Determined criteria are weighted with Shannon entropy method, and Angstrom model and wind power model are used to estimate respectively the solar and wind energy production potential in each city and each month. Assuming the use of proton exchange membrane electrolyzer for hydrogen production, the renewable hydrogen production potential of each city is then estimated based on the obtained wind and solar energy generation potentials. The rankings obtained with MCDMs show that Kermanshah is the best option for renewable hydrogen production, and evaluation of renewable hydrogen production capacities show that Gilangharb has the highest capacity among the studied cities.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.31 no.1
• /
• pp.47-54
• /
• 2011

This experiment was carried out to know adaptability and forage production and quality of corn hybrid for silage at paddy field of Jeonnam and Cheonan region. The growth, forage production and quality of silage corn in normal condition showed much better than drought condition at paddy field. Among the growth characteristics, 'Kangdaok' hybrids was somewhat strong for drought stress, then and good at stem diameter, drought stress, sugar content, stay green, disease and insect resistance. Fresh yield of 'Kwangpyongok' and 'Kangdaok' hybrid at drought paddy field were the highest as 9,714kg and 9,126 kg/ha per ha among corn hybrids. Among the ten hybrids, dry yield of 'Kangdaok' hybrid at drought paddy field was the highest as 5,548 kg per ha. The result of this study showed that 'Kangdaok' hybrid had good growth characters and forage productivity at drought condition and dry matter yield and TDN yield also were 21.6% and 19.3% level compared with normal paddy field.

• IE interfaces
• /
• v.7 no.3
• /
• pp.39-51
• /
• 1994

A CIM implementation case is introduced in this paper. It is accomplished through the integration of two fundamental approaches to production planning and control; JIT and MRP. The resultant system is a hybrid where some JIT methodologies prevail, but the benefits of the MRP are also required. A new BOM structure called 'Family-BOM' is designed for the load leveled production with small lot size and the synchronized production. The overall production planning concept is described with actual data.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2000.11a
• /
• pp.107-111
• /
• 2000