• Journal of Korean Institute of Industrial Engineers
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• v.16 no.2
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• pp.81-89
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• 1990

Transfer pricing mechanism is applied to the problem of input buffer size in the context of interfacing a flexible manufacturing system with multiple following production lines. The size of the input buffers can be determined economically by using non-linear transfer pricing either in a decentralized organization or in a centralized organization. Under the certain conditions, input buffer size determined from this non-linear transfer pricing is more economical than the traditional economic lot size model. The benefit comes from transferring part of FMS' inventory to the following production lines. And this non-linear transfer pricing makes sense if the FMS' unit inventory holding cost is high enough.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.128-139
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• 1998

In this paper, a finite element method for predicting the temperature and stress distributions in micro-machining is presented. The work material is oxygen-free-high-conductivity copper(OFHC copper) and its flow stress is taken as a function of strain, strain rate and temperature in order to reflect realistic behavior in machining process. From the simulation, a lot of information on the micro-machining process can be obtained; cutting force, cutting temperature, chip shape, distributions of temperature and stress, etc. The calculated cutting force was found to agree with the experiment result with the consideration of friction characteristics on chip-tool contact region. Because of considering the tool edge radius, this cutting model using the finite element method can analyze the micro-machining with the very small depth of cut, almost the same size of tool edge radius, and can observe the 'size effect' characteristic. Also the effects of temperature and friction on micro-machining were investigated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05b
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• pp.67-68
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• 2010

Recently, there were not enough studies regarding the mix adjustment and changes of normal physical properties of slump flow type concrete in domestically. Therefore in this paper, it is aimed securing the fundamental data about flow its mix design method by experimental research. The experiment includes the adjustment of the way for slump flow type concrete by the variation of size of coarse aggregate. In the result, it is advisable raising the ratio of fine aggregate and unit water amount by considering the specific surface when increasing the Gmax size.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.221-222
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• 2021

Conventionally, in material management at a construction site, the type, size, and quantity of materials are identified by the eyes of the worker. Labor-intensive material management by manpower is slow, requires a lot of manpower, is prone to errors, and has limitations in that computerization of information on the identified types and quantities is additionally required. Therefore, a method that can quickly and accurately determine the type, size, and quantity of materials with a minimum number of workers is required to reduce labor costs at the construction site and improve work efficiency. In this study, we developed an automated convolution neural network(CNN) and computer vision technology-based rebar size and quantity estimation system that can quickly and accurately determine the type, size, and quantity of materials through images.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.299-312
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• 2013

This study investigated the contaminant loading and characteristics of particle size distributions(PSDs) in the rainfall runoff from two different sources, the pavement road and the ancillary parking lot, and then evaluated four different types of filter media(i.e., EPP, EPS, Zeolite, and Perlite) to treat runoff water. The results showed that runoff from the pavement road contains 5.6 and 20 times higher SS and Pb concentrations, respectively, than that from the parking lot. The particles smaller than $100{\mu}m$ occupied 89.8 % of runoff from the pavement road and 81.4 % of that from the parking lot by volume. The effect of the hydraulic loading, at 950 m/day filtering linar velocity and 40 cm head loss, was largest for Zeolite, followed by Perlite, EPS, and EPP. The return period of tested media calculated by the regression equation for head loss indicated that EPP has the longest life time. The average SS removal rate was similar for all media at between 84.9 % and 89 %, while the effect of various filter column heights was different, showing minimal for EPP and maximum for EPS. All filter media tested demonstrated over 95 % of SS treatment efficiency for the particles bigger than $100{\mu}m$, while for the ones smaller than $100{\mu}m$ the efficiency was in order of EPP(82.4%) > Perlite(76.1 %) > EPS(66.2 %) > Zeolite(65.2 %). The results in conclusion implies that EPP is most effective filter media for the highly contaminated fine particles from road runoff.

• Journal of the Korea Society of Computer and Information
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• v.21 no.6
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• pp.89-96
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• 2016

Damage and attack size of cyber terror is growing to the national size. Not only targeting at a certain companies or individuals but number of cyber terror targeting government bodies or unspecific people is increasing. This is because compared to traditional weapon, input cost is very cheap but ripple effect and shock are much stronger, affecting not only certain groups but also each individuals. 'Anti-terror measurement for protection of nation and public safety' passed last month is one of the renowned measurement passed regardless of objection from opposition party. The opposition party went against this through filibuster for 192 hours but this finally passed National Congress due to lack of oppositions. Korean government is taking post actions after passage of anti-terror measurement. Legislation of enforcement ordinance and regulations is due by 6th of next month. This regulation will be executed from June 4th after legislation. Whenever there is any security issues such as hacking of Korea Hydro and Nuclear Power and National Intelligence Service happens, lot of attention is made to those hackers. However, social recognition or management of those hackers need lot more improvement. Especially, as market of internet of things is increasing, there is an increased anxiety on information security. But as we only rely on security solutions, this problems are keep happening. Therefore, active investment on nurturing hackers who play the role of 'spear and shield' shall be made. Government should put more efforts to allow white hackers to show their abilities. We should have a policy for supporting high-quality programs such as BoB. To make information protection industry into future growth engine, it is necessary to nurture professionals for information protection and white hackers through special programs. Politicians should make related regulations as soon as possible to remove factors that prevent swift management of cyber attack due to lack of legislation. Government should pay lot more financial investment to nurturing professional manpower than now. Protecting life and asset of nation is responsibility and duty of our government. We all should recognize that controlling cyber attack is a part of national defense.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.939-942
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• 2007

Vacuum cleaner is a close life product that can remove various dusts from our surroundings. However well vacuum cleaner clean our environments, many people are looking away from it, due to its loud noise. Its noise causes a big trouble in the usual life, for example, catch calls, TV watching and discussing etc. To reduce these inconveniences, noise reduction methods and systematic design of low noise vacuum cleaner are studied in this paper. At first, sound quality investigation is performed to get the noise level and quality that make people TV watching and catch calls available. Based on the European and domestic customer SQ survey result, sound power, peak noise level and target sound spectrum guideline are studied and introduced. As a second, precise product sound spectrums are designed into each part based on the sound quality result. Fan-motor, brush, mainbody, cyclone spectrums are decided to get the final target sound based on the contribution level. Fan-motor is the major noise source of vacuum cleaner. Specially, its peak sound, RPM peak and BPF Peak, cause the people nervous. To reduce these peak sounds, high rotating impeller and diffuser are focused due to its interaction. A lot of experimental and numerical tests, operation points are investigated and optimization of flow path area between diffusers is performed. As a bagless device, cyclones are one of the major noise sources of vacuum cleaner. To reduce its noise, previous research is used and adopted well. Brush is the most difficult part to reduce noise. Its noise sources are all comes from aero-acoustic phenomena. Numerical analysis helps the understanding of flow structure and pattern, and a lot of experimental test are performed to reduce the noise. Gaps between the carpet and brush are optimized and flow paths are re-designed to lower the noise. Reduction is performed with keeping the cleaning efficiency and handling power together and much reduction of noise is acquired. With all above parts, main-body design is studied. To do a systematic design, configuration design developments technique is introduced from airplane design and evolved with each component design. As a first configuration, fan-motor installation position is investigated and 10 configuration ideas are developed and tested. As a second step, reduced size and compressed configuration candidates are tested and evaluated by a lot of major factor. Noise, power, mass production availability, size, flow path are evaluated together. If noise reduction configuration results in other performance degrade, the noise reduction configuration is ineffective. As a third configuration, cyclones are introduced and the size is reduced one more time and fourth, fifth, sixth, seventh configuration are evolved with size and design image with noise and other performance indexes. Finally we can get a overall much noise level reduction configuration. All above investigations are adopted into vacuum cleaner design and final customer satisfaction tests in Europe are performed. 1st grade sound quality and lowest noise level of bagless vacuum cleaner are achieved.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.331-341
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• 2011

This paper considers an inbound lot-sizing and outbound dispatching problem for a single product in a thirdparty logistics (3PL) distribution center. Demands are dynamic and finite over the discrete time horizon, and moreover, each demand has a delivery time window which is the time interval with the dates between the earliest and the latest delivery dates All the product amounts must be delivered to the customer in the time window. Ordered products are shipped by multiple vehicle types and the freight cost is proportional to the vehicle-types and the number of vehicles used. First, we formulate a mixed integer programming model. Since it is difficult to solve the model as the size of real problem being very large, we design a conventional genetic algorithm with a local search heuristic (HGA) and an improved genetic algorithm called adaptive genetic algorithm (AGA). AGA spontaneously adjusts crossover and mutation rate depending upon the status of current population. Finally, we conduct some computational experiments to evaluate the performance of AGA with HGA.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.373-380
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• 2007

In this paper, we consider a new lot-sizing and scheduling problem (LSSP) that minimizes the sum of production cost, setup cost and inventory cost. Setup carry-over and overlapping as well as demand splitting are considered. Also, maximum number of setups for each time period is not limited. For this LSSP, we have formulated a mixed integer programming (MIP) model, of which the size does not increase even if we divide a time period into a number of micro time periods. Also, we have developed an efficient heuristic algorithm by combining decomposition scheme with local search procedure. Test results show that the developed heuristic algorithm finds good quality (in practice, even better) feasible solutions using far less computation time compared with the CPLEX, a competitive MIP solver.

• Korean Institute of Interior Design Journal
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• no.12
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• pp.50-56
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• 1997

In the past thirty years, apartment house has been greatly developed and the housing supply has improved some degree. However, the fact is that interior space planning of apartment house still has a lot of problems. The purpose of this study is to research the change of interior room. The 160 examples of unit floor plan(40-85m2 i.e. 12.1py-25.7py) were selected and classified according to master bedroom type and living room area when was constructed by the city of Seoul and KNHC from 1970 to 1990. And then, the change of each area, size and ratio were analyzed and researched. The result of this research can be summarized as follows: 1. Size of unit floor plan was on the increase from 16.02py to 17.86py. 2. 2 bedroom type, master bedroom showed a rise of size and occupancy ratio. Living room grew larger than 1982-1991 for size and occupancy ratio. 3. 3 bedroom type, master bedroom was increased in size and occupancy ratio was reduced to 19.99%. Size of living room became broader than master bedroom and occupancy ratio(1972-1981) increased over 1982-1991. Through this analysis and research, this study is to provide the basic data for actural design process and to suggest future trend of apartment house.