• The Journal of the Acoustical Society of Korea
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• v.38 no.1
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• pp.9-22
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• 2019

In this paper, we propose a method that can be applied to the efficient implementation of multi-channel active noise controller. Since the normalized MFxLMS (Modified Filtered-x Least Mean Square) algorithm for the multi-channel active noise control requires a large amount of computation, the difficulty has lied in implementing the algorithm using a low-cost MCU (Microcontoller Unit). We implement the multi-channel active noise controller efficiently by optimizing the software based on the features of the MCU. By maximizing the usage of single-cycle MAC (Multiply- Accumulate) operations and minimizing move operations of the delay memory, we can achieve more than 3 times the performance in the aspect of computational optimization, and by parellel processing using the auxillary processor included in the MCU, we can also obtain more than 4 times the performance. In addition, the usage of additional parts can be minimized by maximizing the usage of the peripherals embedded in the MCU.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.1007-1015
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• 2014

The importance of construction waste reusing and recycling is becoming increasingly large because the demolition industry is in current trend to pursue for sustainable growth. As the considering situation of the domestic housing construction and existing house, a scale of demolition industry is expected to be increased continuously. But the related cost regulations that are used in tendering in the demolition industry are insufficient, also the computer system for estimating the demolition costs have not been developed yet. Therefore, in this study suggests man-hours of 21EA items which are utilized to estimate demolition cost and work rate of $1.0m^3$ breaker which is used mostly in domestic demolition industry after analyzing a case study for deconstruction works. The computer system is developed for the estimating demolition cost easily, which are including five modules such as a project information, a unit cost management, a standard unit cost table, a bill of quantity, and a reporting system. This computer system is possible to apply for estimating cost of both mechanical demolition and blasting demolition. The biggest advantage of this system is to estimate cost to utilize standard WBS which is linked with standard unit table and each DB. This can help unskilled users use easily for it.

• Journal of IKEEE
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• v.17 no.3
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• pp.352-359
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• 2013

This paper proposes an entropy coding unit for H.264/AVC baseline profile. Entropy coding requires code tables for macroblock encoding. There are patterns in codewords of each code tables. In this paper, the patterns between codewords are analyzed to reduce the hardware cost. The entropy coding unit consists of Exp-Golomb unit and CAVLC unit. The Exp-Golomb unit can process five code types in a single unit. It can perform Exp-Golomb processing using only two adders. While typical CAVLC units use various code tables which require large amounts of resources, the sizes of the tables are reduced to about 40% or less of typical CAVLC units using relationships between table elements in the proposed CAVLC unit. After the Exp-Golomb unit and the CAVLC unit generate code values, the entropy unit uses a small size shifter for bit-stream generation while typical methods are barrel shifters.

• Journal of Advanced Navigation Technology
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• v.20 no.6
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• pp.511-518
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• 2016

RAPCON non only controls landing/take-off procedures but also approaching air traffics within 60-70 NM range of air force base. This paper, first of all, tries to research the failure rate per operation hours, mean time between failure (MTBF) of RAPCON according to six blocks such as interrogator, receiver, power unit, display unit, data process unit and antenna. In addition, this paper estimates the maintenance cost over next 10 months based on 50 monthly maintenance cost data. Considering the maintenance cost data from RAPCON which has been used over designed service life span, it is no doubt the forecasted data proved the monthly cost would go up incrementally during the rest of economic life of the facility. Such research result is also proven to be the same with the result of bathtub curve data during operating life.

• Journal of the Korean housing association
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• v.25 no.1
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• pp.51-61
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• 2014

The purpose of this study was to explore housing characteristics of young single- or two-person households in the U.S. metropolitan urban areas and determinants of their housing cost burden. Total 764 single-person households, 744 two-person households and 424 households with three or more persons were selected from the 2011 American Housing Survey public-use microdata for the study based on specific sampling criteria. The major findings are as follows: (1) In comparisons with larger households, single- or two-person households were characterized to be headed by younger householders, to have less income, and to have a greater proportion of households living in central cities of metropolitan areas, renting housing units, living in smaller size units or multifamily structures; (3) housing cost of single- or two-person households were significantly less than a larger households while housing costs per unit square footage (SQFT) of single- or two-person households was significantly greater; (4) regardless of the household size, there are many household headed by young college graduates paying too much of their income for housing, and single-person households were found to have the greatest housing cost burden; and (5) a linear combination of low-income status, monthly housing costs per unit SQFT, annual household income, and unit SQFT per person was found to be most efficient to predict single- or two-person households with housing cost burden.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.31-41
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• 2006

The analysis used in this work was cost-benefit analysis method. All future costs and returns of a given mushroom house were discounted to the time of initial investment (present) by means of 3.5% discount rate. Then the cost of ownership was compared to the return from the system. This analysis method has been developed and coded into a balance sheet for use on a EXCEL program. Using this programmed analysis,a large number of the case studies were examined using different combinations of economic conditions. These results will be very useful to individuals considering investment in a mushroom house, or any similar production system. By the way of the sensitivity analysis for each important parameter, the change of the marginal cost-benefit period could be finally determined. These parameters were typically construction cost of mushroom house, cost of cooling system, required cooling and heating energy amounts, unit price of mushroom media bottle, growing number of media bottles, production weight per unit bottle, sale price of mushroom, and annual number of growing period, etc.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.294-295
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• 2018

Nowadays, the construction industry utilizes 3D models in the designing process, on which research is being conducted to establish an automated system for project cost estimation in connection with information related to construction such as material unit costs and wages, beyond the level of design interference review and construction quantity estimation. In this process, the project cost is estimated in connection with unit price data after takeoff the quantity based on the 3D model attributes and data types. A way to reduce cost and risk would be first developing prototypes of some of essential buildings and works, comparing and validating the outcomes, and then extending to the whole scope, because estimates differ on the basis of the scope and level of 3D design models as well as the data accuracy. This study analyzes case studies of project cost estimation by computing the quantity on the basis of 3D model in the construction industry and explores methodologies and management measures applicable for estimating nuclear power plant construction project costs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.21-29
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• 2015

A steady-state controllable M/G/1 queueing model operating under the {T:Min(T,N)} policy is considered where the {T:Min(T,N)} policy is defined as the next busy period will be initiated either after T time units elapsed from the end of the previous busy period if at least one customer arrives at the system during that time period, or after T time units elapsed without a customer' arrival, the time instant when Nth customer arrives at the system or T time units elapsed with at least one customer arrives at the system whichever comes first. After deriving the necessary system characteristics including the expected number of customers in the system, the expected length of busy period and so on, the total expected cost function per unit time for the system operation is constructed to determine the optimal operating policy. To do so, the cost elements associated with such system characteristics including the customers' waiting cost in the system and the server's removal and activating cost are defined. Then, procedures to determine the optimal values of the decision variables included in the operating policy are provided based on minimizing the total expected cost function per unit time to operate the queueing system under considerations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.457-468
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• 2011

Recently, the non-vibration mass excavation method is used on sewage pipes and road construction sites in Jeju. However, a construction cost estimation based on the unit quantity does not provide a proper unit price. In this study, a comparison of the productivity of the standard quantity-per-unit costing method and the one of the work crew combination method was made based on the site monitoring of the non-vibration mass excavation method that is used in construction sites near Jeju. For this, data of 35 sites were collected: a regression equation was derived from the 30 data, and verification was carried out through the remaining 5 data. The analysis concluded that a day's workload is $16.43m^3$. In addition, a combination of the equipment considering the site conditions and the amount of labor, which varies with the number of work crew was obtained in order to estimate the construction cost of the work crew combination method. The construction cost was calculated based on the one-day workload ($16.43m^3$) derived from the regression analysis. The cost then was analyzed and compared with the standard quantity-per-unit costing method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.273-285
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• 2012

Current TMDL based on the 'Polluter Pays Principle' in Republic of Korea is individually operated by each local government for the designed allocated pollution load of unit watershed and unit district. However, unlike the motion of the air contaminants, the polluted contaminants in a river move from upstream to downstream, and a river can affect to districts more than two. In addition, a decision making on the construction of a sewage treatment facilities follows the concept of 'economy of scale'. These reasons support the collaboration among local governments in order to reduce the costs in improving water quality. This study suggested a method to reduce water quality management cost by redistributing reduction load considering cost-effectiveness for an entire watershed. The assessment on the suggested method is conducted in Youngsan river watershed. Without variation in total load, reduction load assigned for unit watershed and unit district is retributed in the region where pollutant source is concentrated, and then water quality and cost reduction improved from the redistribution of reduction load is analyzed. The results show that the cost saved by the suggested method is KRW 124 billion for scenario-1 and 172 billion for scenario-2 considering total cost of KRW 788 billion for the existing plan. We expect that the suggested method is a good example to reduce water quality management cost in local governments for TMDL.