• International journal of advanced smart convergence
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• v.4 no.2
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• pp.138-144
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• 2015

Digital filters are extensively used in the world of communication. In order to design a digital finite impulse response (FIR) filter that satisfies all the required conditions is challenging. In this paper, design techniques of digital low pass FIR filters using Rectangular window method, Hamming window, Hanning window, and Optimal Parks McClellan method are presented. The stability, number of components required and filter coefficients are demonstrated for different design techniques. It is demonstrated that filter design using hamming window is comparatively better than rectangular and hanning window though the components required for all of the windowing technique are same, hamming shows higher stability. The stability is shown with the help of magnitude and phase spectrum of each window. Simulation is carried out using MATLAB and comparisons are made entirely based on the output of the simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.205-209
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• 1997

One objective of the u control chart is to detect changes of mean nonconformities per unit occurred owing to various causes. This paper shows the detection probability using the Poisson distribution for various parameters, that is, subsample size n, mean nonconformities per unit $u_o$, and $u_o's$ change ratio k. We find that (1) as $u_o$ increases the smaller n is required for the same detection probability and the same change ratio; (2) as k gets away from 1 the smaller n is required; (3) the bigger n is required for the bigger detection probability. Several tables are given from our findings and are hoped to be used as guidelines for u chart users.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.213-214
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• 2017

In this study, a survey was conducted to investigate the environmental degradation factors of specific areas in residential apartment underground structures an'd the required performance attributes for waterproofing material. Based on the survey, it was concluded that joint displacement of concrete is the highest cause for problems, and the required performance was determined to high wet surface adhesion performance for waterproofing materials.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11A
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• pp.898-903
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• 2009

In this paper, the required frequency bandwidth for short range communications and mobile communication networks is analyzed for the matured Personal Environment Service, which establishes intelligent personal living environment with connecting the mobile phone and living appliances to WPAN, mobile communication networks, and Internet. In spite of rough estimation of the service needs, this paper shows the calculation method of required frequency bandwidth for the service and the considerations for the Ubiquitous era in advance.

• Computers and Concrete
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• v.11 no.3
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• pp.183-199
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• 2013

To select a most desired mix proportion that meets required performances according to the quality of recycled aggregate, a large number of experimental works must be carried out. This paper proposed a new design method for the mix proportion of recycled aggregate concrete to reduce the number of trial mixes. Genetic algorithm is adapted for the method, which has been an optimization technique to solve the multi-criteria problem through the simulated biological evolutionary process. Fitness functions for the required properties of concrete such as slump, density, strength, elastic modulus, carbonation resistance, price and carbon dioxide emission were developed based on statistical analysis on conventional data or adapted from various early studies. Then these fitness functions were applied in the genetic algorithm. As a result, several optimum mix proportions for recycled aggregate concrete that meets required performances were obtained.

• Journal of The Korea Institute of Healthcare Architecture
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• v.10 no.2
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• pp.7-18
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• 2004

As a society advances and develops more rapidly, there is a corresponding increase in an aging population; and therefore, transportation and transportation needs develop in a complicated way. In these times, medical rehabilitation services are required and the demands for these services will increase as time passes. Moreover, the scope of disability as defined by the government has been expanded owing to the welfare policy for the disabled. Therefore, the number of disabled who require medical services is on the rise. Along with an increase in medical rehabilitation demands, the necessity for medical rehabilitation increases as well and its role becomes more diverse on a wider spectrum. However, architectural studies on rehabilitation facilities have been insufficient and there are many problems currently in facilities operations. This study aims to present a spatial organization system along with required space that would form the basis for the most effective spatial plan and facility operation for rehabilitation hospitals.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.6 no.1
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• pp.21-29
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• 1998

The purpose of the present paper is to determine the time required and error tolerance limits for flight data computation. The results of statistical analysis showed that the calculator side computation required about 50 seconds for each question and wind side computation needed about 115 seconds for each question. In case of error tolerance limits, it was found that the error tolerance limit for altitude computation war 90 feet and two knots of interval was recommanded for the speed computation in calculator side, and one degree of interval for heading computation and five knots interval for speed computation in wind side.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.395-398
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• 2006

this paper provides a novel method to start the linear engine coupled linear generator from dead stop to its final steady state operation. This method depends mainly to use the linear generator mounted on the shaft of the linear engine to provide the required thrust force to move and oscillate the linear engine from bottom to top dead centers. It is a cost effective approach to start the internal linear combustion engine using its coupled tubular permanent magnet linear generator proposed here. This linear generator operates in this case in motoring mode, providing the required thrust force by feeding this linear generator phases with currents by using a three phase PWM inverter controlled by position feedback scheme. In order to provide the desired thrust force with specific value and direction, a position feedback is required to control the free piston engine motion through controlling the inverter switches using PWM control scheme.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.58-58
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• 2000

Recently low resistance of bus line is required for large screen size RFT-CLD panels. As a result, lower resistance Al-alloy is currently reviewed extensively. The resistivity is required smaller than 10$\mu$$\Omega$cm and high resistance of chemical attack is required. In this paper, Al-W thin film were deposited on glass substrates by D.C magnetron sputtering system under various condition for high chemical resistance. Its properties were characterized by SEM, AFM, XRD, 4-point-probe, and cyclic voltammertry. The optimal condition of Al-W was 10$0^{\circ}C$, 100W, 0.4Pa, 23sccm(Ar) and 35$0^{\circ}C$, 20min. annealing. At that condition the resistivity of Al-W(3 wt.%) was about 11$\mu$$\Omega$cm. And when wt.% of W in Al-W alloy was higher than about 4%, Al-W alloy thin film has high chemical resistance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.357-360
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• 2008

In roll forming process, a sheet metal is continuously progressively formed into a product with required cross-section and longitudinal shape, such as a circular tube with required diameter, wall-thickness and straightness, by passing through a series of forming rolls in arranged in tandem. In this process, each pair of forming rolls installed in a forming machine play a particular role in making up the required cross-section and longitudinal shape of the product. In recent years, that process is often applied to the bumper rail in the automotive industries. In this study, a optimal SILL SIDE manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle. And also effects of the process parameters on the final shape formed by roll forming defects were evaluated.