• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.5
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• pp.93-99
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• 2017

A model was developed using Artificial Neural Networks (ANNs) based on Principal Component Analysis (PCA), to accurately predict the air humidity inside an experimental greenhouse located in Daegu (latitude $35.53^{\circ}N$, longitude $128.36^{\circ}E$, and altitude 48 m), South Korea. The weather parameters, air temperature, relative humidity, solar radiation, and carbon dioxide inside and outside the greenhouse were monitored and measured by mounted sensors. Through the PCA of the data samples, three main components were used as the input data, and the measured inside humidity was used as the output data for the ALYUDA forecaster software of the ANN model. The Nash-Sutcliff Model Efficiency Coefficient (NSE) was used to analyze the difference between the experimental and the simulated results, in order to determine the predictive power of the ANN software. The results obtained revealed the variables that affect the inside air humidity through a sensitivity analysis graph. The measured humidity agreed well with the predicted humidity, which signifies that the model has a very high accuracy and can be used for predictions based on the computed $R^2$ and NSE values for the training and validation samples.

• Environmental and Resource Economics Review
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• v.15 no.3
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• pp.531-553
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• 2006

As energy conservation can be realized through changes in the composition of goods and services consumed, there is a need to assess indirect and total household energy requirements. The Korean household sector was responsible for about 55% of the country's primary energy requirement in the period from 1990 to 2000. And more than 60% of household energy requirement was indirect. Thus, indirect and total rather than direct household energy requirements should be the target of energy conservation policies. Increases in household consumption expenditure were responsible for a relatively high growth of energy consumption. Switching to consumption of less energy intensive products and decrease in energy intensities of products contributed substantially to reduce the increase in total household energy requirement.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.141-148
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• 2003

A data collection of a liquid radioactive waste treatment process of a research organization became necessary while developing the RAWMIS(Radioactive Waste Management Integration System) which it can generate personal history management for efficient management of a waste, documents, all kinds of statistics. This paper introduces an input and output application program design to do to database with data in the results and a stream process of a treatment that analyzed the waste occurrence present situation and data by treatment process. Data on the actual treatment process that is not limited experiment improve by a document, human traces, saving of material resources and improve with efficiency of tracking about a radioactive waste and a process and give help to radioactive waste material valance and inventory study.

• Journal of Sensor Science and Technology
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• v.11 no.3
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• pp.132-137
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• 2002

The single crystal of $LiTaO_3$ ($x-112^{\circ}$ y) has very stable thermal characteristics in a piezoelectric transformer. In this paper, a piezoelectric transformer made of the crystal is newly designed and its operating characteristics are analyzed. The length of the transformer is determined as twice as its width for Lame'-mode because the single crystal of $LiTaO_3$ has low electro-acoustic efficiency. The electric and vibrational characteristics of the transformer is simulated by the PSpice program, and its results are compared to experimental ones. As the results, the ratio of output voltage to input shows large than 10 at 290.83[kHz], which is the frequency coupled the 2nd harmonic for length and the fundamental for width of the Lame'-mode transformer.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.115-121
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• 2009

The paper presents a signal-based damage detection algorithm of ARX model using dynamic acceleration data. An ARX model correlates acceleration data measured at two locations in a structure by considering those two sets of data as input and output signals. For detecting damage, the error between the measured data and the predicted response from the defined ARX model is computed in time and used for a statistical evaluation. A normal distribution function from the error in time is constructed and its statistical characteristic values are used for the evaluation of damage. By comparing the normal distribution functions before and after damage, three different types of damage indices are proposed. The efficiency and limitation of the proposed algorithm with the statistical evaluation of damage indices have been examined and discussed through laboratory experiments.

• Journal of Information Management
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• v.42 no.3
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• pp.55-69
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• 2011

In the modern scientific R&D, the efficient acquisition, curation, analysis and visualization are core elements of the science development. The value of scientific data is very important in data intensive research. An output of scientific data is drastically increasing. However we have only each individual system of scientific data in now. Therefore We feel a lack of efficiency of scientific data. In this paper, We analyze an economic ripple effects in terms of production inducement effect, added value inducement effect, labor inducement effect and forward backward linkage effect of national scientific data center construction using an input-out analysis of the bank of Korea(2009). We also examine an economic propriety of national scientific data center construction.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.6
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• pp.33-41
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• 2014

In this paper, we propose a D flip-flop based on quantum-dot cellular automata(QCA) clocking and design a programmable quantum-dot cell(QPCA) structure using the proposed D flip-flop. Previous D flip-flops on QCA are that input should be set to an arbitrary value, and wasted output values exist because it was utilized to duplicate by clock pulse and QCA clocking. In order to eliminate these defects, we propose a D flip-flop structure using binary wire and clocking technique on QCA. QPCA structure consists of wire control logic, rule control logic, D flip-flop and XOR logic gate. In experiment, we perform the simulation of QPCA structure using QCADesigner. As the result, we confirm the efficiency of the proposed structure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.277-290
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• 1999

A simulation using the finite-difference time-domain method to analyze the electromagnetic interactions between a cellular phone and the human body was conducted, and a synthesis of a bone-equivalent material to make a human head phantom was performed. A test model of the cellular phone was fabricated to measure its reflection coefficient and radiation pattern in the free space. Various effects of the human body on the characteristics of the phone, such as input impedance, reflection coefficient, radiation pattern, and radiation efficiency are analyzed as the distance between the head and the phone antenna varies. When the phone was operated close to the head, the resonant frequency of the antenna decreased by up to 12%. With the output power of 0.6W, as long as the distance was larger than 30mm, the 1-g averaged peak SAR was below the ANSI/IEEE safety guideline, 1.6 W/kg. To synthesize the bone-equivalent material, an epoxy with hardener and a graphite powder were used as basis ingredients, and a small amount of a conducting epoxy was added to control the conductivity of the material. A material having a relative permittivity of 18.04 and a conductivity of 0.347, which are close to those of the bone at 850 MHz, was synthesized.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.1
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• pp.92-95
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• 2016

In this paper, an UHF-band 1 kW solid-state pulsed power amplifier was designed and implemented for the thermoacoustic imaging(TAI) at 900 MHz. The designed power amplifier has a pulse width of $80{\mu}s$ and a duty cycle of 1 % for short-pulse operation. The overall amplifier was implemented by combining of 16 single-power amplifiers adopting MRFE6P9220HR3 LDMOSFET using wilkinson power dividers. The solid-state pulsed power amplifier shows 25 % drain efficiency with a gain of 76.2 dB when the output power is 60.2 dBm for a -16 dBm input power at center frequency.

• Journal of Digital Contents Society
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• v.6 no.2
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• pp.101-106
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• 2005

In this paper, performance evaluation of mobile access layer for multiple-input multiple-output (MIMO) MultiCarrier(MC)/CDMA 16 QAM system is considered to mitigate multiple access interference and enhance system channel capacity in Rayleigh wireless fading channel. Traditionally, multi-path is viewed as an undesirable feature of wireless communications. Therefore, diversity and adaptive array schemes are proposed to mitigate its effects. Recently, to increase the spectrum efficiency and the link reliability, MIMO schemes is devised to exploit multi-path in a scattering wireless channel. In particular, the channel capacity of MIMO-MC/CDMA 16 QAM system is evaluated according to Eb/No, Mc, p. From the results, in order to improve the channel capacity, the signals at various elements must be uncorrelated. And if the paths are correlated due to inappropriate spacing or mutual coupling effects, the channel capacity of MIMO-MC/CDMA 16 QAM system becomes substantially smaller.