• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.636-647
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• 2012

Construction projects have become so large, complicated and incredibly high-tech that process management is currently considered one of the most important issues. Unlike typical manufacturing industries, most major construction activities are performed in the open air and thus are exposed to various environmental factors. Many studies have been conducted with the goal of establishing efficient techniques and tools for overcoming these limitations. Productivity analysis and prediction, one of the related research subjects, must be considered when evaluating approaches to reducing construction duration and costs. The aim of this research is to present a quantified impact analysis of construction delay factors on construction productivity of a steel staircase system, which has been widely applied to high rise building construction. It is also expected to improve the process by managing the factors, ultimately achieving an improvement in construction productivity. To achieve the research objectives, this paper analyzed different delay factors affecting construction duration by means of multiple regression analysis focusing on steel staircase systems, which have critical effects on the preceding and subsequent processes in structure construction. Statistical analysis on the multiple linear regression model indicated that the environment, labor and material delay factors were statistically significant, with 0.293, 0.491, and 0.203 as the respective quantified impacts on productivity.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.219-222
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• 2004

There are several factors that disturb an Ultra-Wideband (UWB) radio propagation in an indoor environment such as path loss, shadowing and multipath fading. These factors directly affect the quality of the received signal. In this paper, we investigated the influence of the human body shadowing on UWB propagation based on measured wireless channel in an anechoic chamber. The characteristics of the UWB channel including the transmitter and the receiver antenna effects are acquired over the frequency bandwidth of 3${\sim}$11 GHz. The major factors such as the power delay profile (PDP), the angular power distribution (APD), the pulse distortion and the RMS delay spread caused by the human body shadowing are presented.

• Journal of Astronomy and Space Sciences
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• v.27 no.1
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• pp.21-30
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• 2010

In processing space geodetic data, mapping functions are used to convert the tropospheric signal delay along the zenith direction to the line of sight direction. In this study, we compared three mapping functions by evaluating their effects on the tropospheric signal delay and position estimates in GPS data processing. The three mapping functions tested are Niell Mapping Function (NMF), Vienna Mapping Function 1 (VMF1), and Global Mapping Function (GMF). The tropospheric delay and height estimates from VMF1 and GMF are compared with the ones obtained with NMF. The differences among mapping functions show annual signals with the maximum occurring in February or August. To quantitatively estimate the discrepancies among mapping functions, we calculated the maximum difference and the amplitude using a curve fitting technique. Both the maximum difference and amplitude have high correlations with the latitude of the site. Also, the smallest difference was found around $30^{\circ}N$ and the amplitudes increase toward higher latitudes. In the height estimates, the choice of mapping function did not significantly affect the vertical velocity estimate, and the precision of height estimates was improved at most of the sites when VMF1 or GMF was used instead of NMF.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.10
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• pp.511-520
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• 2007

Decay usage scheduling algorithm gives preference to processes that have consumed little CPU in the recent past. It has been widely-used in time-sharing systems such as UNIX, where CPU-intensive processes and interactive processes are mixed. However, there has been no sound understanding about the mixed effects of decay usage parameters on the service performance. This paper empirically analyzes their effects in terms of the resulting service bandwidth and delay Based on such empirical analysis, we derive the clear meaning of each parameter. Such analysis and understanding provides a basis of controlling decay usage parameters for desirable service provision as required by applications.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.3
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• pp.4163-4170
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• 1976

This study was conducted to investigate the effect of starch as a retarder on the maximum dry density and the unconfined compressive strength of soil cement mixtures for varied starch contents (0-3%), cement contents (3-12%), and delay times (0-6hrs) in four soils. The experimental results obtained from maximum dry density and unconfined compressive strength tests are as follows: 1. Maximum dry density and unconfined compressive strength were increased greatly in soil cement mixtues rwhen starch was added as retarder but their value schanged according to soil varieties. 2. Maximum dry density showed at about 0.5 percent to 1.0 percent of starch in KY soil and about 2.0 percent to 2.5 percent in SS soil when delay time was changed in 2.4, and 6 hours in compaction test. 3. The larger content of cement was, the bigger effects of maximum dry density and compressive strength were in soil cement. mixtures. 4. As delay time changed 2.4, and 6 hours in compaction test, 7-day unconfined compressive strength showed the biggest value at about 0.5 percent of starch in KY soil and 2.0 percent in SS soil, and the maximum value of 28-day unconfined compressive strength showed at about 0.5 percent in KY soil and 1.5 percent in SS soil.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.11
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• pp.1707-1718
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• 2009

This study examines the effects of perceived risks on purchase decision behavior among Internet fashion consumers. The study survey used a self-administered questionnaire and a total data of 244 responses were used for analysis. The results of this study are as follows: First, the perceived risks consist of 6 factors, quality risk, counterfeit product risk, credit dealing risk, social/psychological risk, size and appearance risk, and delivery risk. The purchase decision behavior consist of 3 factors, delay of purchase decision, website switching, and offline conversion behavior. Second, purchase time positively affected the quality risk and credit dealing risk. Purchase frequency negatively affected the quality risk and credit dealing risk. Third, the quality risk, size and appearance risk, counterfeit product risk, and credit dealing risk positively affected the delay of purchase decisions. Quality risk and counterfeit product risk positively affected website switching. In addition, quality risk, social/psychological risk, and credit dealing risk positively affected the offline conversion behavior. Fourth, credit dealing risk negatively affected a short term purchase intention and the delivery risk negatively affected a long term purchase intention. The social/psychological risk and credit dealing risk negatively affected the repurchase intention.

• Journal of IKEEE
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• v.21 no.4
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• pp.424-427
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• 2017

Smith predictor can't be applied to the time delay systems that have poles near the origin or a pure integrator or a modeling error, because of occurring the steady state error for the step disturbance. In this paper, a new Smith predictor controller for these systems is designed to eliminate the effects of the disturbance. A disturbance observer to estimate a disturbance is proposed and a new controller is designed using the estimated disturbance. As a result, the new controller can eliminate the effects of the disturbance and modeling error. The simulation results for the steam superheater and the steam pressure systems verify the efficiency of the proposed controller.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.294-303
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• 2022

The purpose of this study is to examine the effects of sensory integration training on children with developmental delays. To achieve this goal, an educational experiment is conducted in five main areas: gross motor ability, fine motor ability, adaptive ability, language and social ability in children with developmental delay. The study subjects were children with developmental delays aged 3-6 years diagnosed at Beijing Institute of Pediatrics and Beijing Medical University and received sensory integration intervention and homebased training at the Golden Rain Forest Beijing Tongzhou Center from 2018 to 2021. According to the purpose of the analysis, the data collected are subjected to descriptive statistics using SPSS 21.0 statistical program, Two-way MANOVA analysis, and data analysis method of multivariate analysis is used to process the collected data. In addition, a total of 39 subjects were selected, including 19 children who received sensory integration training and 20 children who only received family training. The results show that the sensory integration training group outperformed the home training group in all aspects and developmental quotient, but the home training group also showed higher levels of significance for improvements in gross motor, fine motor and developmental quotient.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.68-69
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• 2011

Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between the two conduction modes. Especially, the time delay can provide an accurate LED current for the peak current controlled (PCC) buck converter with a wide input voltage. Experimental results are presented for the PCC buck LED driver with constant-frequency controller.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.975-978
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• 1999

The transmission line effects of IC interconnects have a substantial effect on a hish-speed VLSI circuit performance. The effective transmission lime parameters are changed with the increase of the operation frequency because of the skin of the skin effect, proximity effect, and silicon substrate. A new signal delay estimation methodology based on the RLC-distributed circuit model is presented ［2］. The methodology is demonstrated by using SPICE simulation and a high-frequency experiment technique.