• Journal of Industrial Convergence
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• v.18 no.2
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• pp.69-75
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• 2020

Industrial IoT has much interested in wireless mesh networks (WMNs) due to cost effectiveness and coverage. According to the advance in caching technology, WMNs have been researched to overcome the throughput degradation of multihop environment. However, there is few researches of cache power consumption models for WMNs. In particular, a wired line based cache power consumption model in content-centric networks is not still proper to WMNs. In this paper, we split the amount of cache power from the idle power consumption of CPU, and then the cache hit ratio proportional power consumption model (CHR-model) is proposed. The proposed CHR-model provides more accurate power consumption in WMNs, compared with the conventional cache power efficiency based consumption model (CPE-model). The proposed CHR-model can provide a reference model to improve energy-efficient cache operation for Industrial IoT.

• Progress in Medical Physics
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• v.23 no.4
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• pp.303-308
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• 2012

The Geant4 based Monte Carlo code for the application of stereotactic radiosurgery was developed. The probability density function and cumulative density function to determine the incident photon energy were calculated from pre-calculated energy spectrum for the linac by multiplying the weighting factors corresponding to the energy bins. The messenger class to transfer the various MLC fields generated by the planning system was used. The rotation matrix of rotateX and rotateY were used for simulating gantry and table rotation respectively. We construct accelerator world and phantom world in the main world coordinate to rotate accelerator and phantom world independently. We used dicomHandler class object to convert from the dicom binary file to the text file which contains the matrix number, pixel size, pixel's HU, bit size, padding value and high bits order. We reconstruct this class object to work fine. We also reconstruct the PrimaryGeneratorAction class to speed up the calculation time. because of the huge calculation time we discard search process of the ThitsMap and used direct access method from the first to the last element to produce the result files.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.6
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• pp.55-62
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• 2005

This paper proposes a method to recognize a face using DCT/LDA where LDA is applied to DCT coefficients of an input face image. In the proposed method, SSS problem of LDA due to less number of training data than the size of feature space can be avoided by expressing an input image in low dimensional space using DCT coefficients. In terms of the recognition rate, both the proposed method and the PCA/LDA method have shown almost equal performance while the training time of the proposed method is much shorter than the other. This is because DCT has the fixed number of basis vectors while the property of energy compaction rate is similar to that of PCA. Although depending on the number of coefficients employed for the recognition, the experimental results show that the performance of the proposed method in terms of recognition rate is very comparable to PCA/LDA method and other DCT/LDA methods, and it can be trained 13,000 times faster than PCA/LDA method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.2
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• pp.68-76
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• 2010

Touch-enabled technology is increasingly being accepted as a main communication interface between human and computers. However, conventional touchscreen technologies, such as resistive overlay, capacitive overlay, and SAW(Surface Acoustic Wave), are not cost-effective for large screens. As an alternative to the conventional methods, we introduce a newly emerging method, an optical imaging touchscreen which is much simpler and more cost-effective. Despite its attractive benefits, optical imaging touchscreen has to overcome some problems, such as heavy computational complexity, intermittent ghost points, and over-sensitivity, to be commercially used. Therefore, we designed a hardware controller for signal processing and multi-coordinate computation, and proposed Infrared-blocked DA(Dark Area) manipulation as a solution. While the entire optical touch control took 34ms with a 32-bit microprocessor, the designed hardware controller can manage 2 valid coordinates at 200fps and also reduce energy consumption of infrared diodes from 1.8Wh to 0.0072Wh.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.691-698
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• 2017

In this study, the injector transfer function (ITF) of a gas-gas coaxial jet-swirl injector is measured by applying excitation to jet or swirl flow using a loudspeaker. As a result of measuring the ITF according to the variation of feed system length, the ITF peak occurs at the resonance frequency of the space where the perturbed flow passes. When applying the excitation to the jet flow, as the jet flow increases up to 56 slpm, the magnitude of ITF decreases, and ITF increases thereafter. Therefore the larger the velocity difference between the jet and the swirl flow, the larger the ITF. In the case of the swirl excitation, the ITF decreases as the jet flow increases because of the decrease of the energy with respect to the constant flow at the downstream. This difference is caused by the location of the hot wire anemometer on the downstream of the injector center axis.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1862-1866
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• 2010

기후변화에 관한 정부간 협의체(International Panel on Climate Change, IPCC) 4차 보고서에는 21세기말 지구의 평균기온이 최대 $6.4^{\circ}C$ 까지 더 상승할 것으로 전망하였다(IPCC, 2007). 지구의 평균온도는 지난 100년 동안 $0.74^{\circ}C$ 상승하였으며 그중 0.45%는 최근 25년간 상승한 것이며 이것은 지난 100년 보다 2.4배나 빠르게 상승하고 있는 추세이다. 우리나라의 경우 기온이 전 지구평균기온에 비해 2배 이상 높은 $1.5^{\circ}C$정도 상승 하였다. 또한 온실가스 증가 속도는 다른 나라에 비해 빠르게 진행되고 있으며, 1990년에서 지난 2001년간 다른 OECD국가들과 비교했을 때 가장 빠르게 증가하고 있을 뿐 아니라($CO_2$배출량은 OECD국가 중 10위) 현재와 같은 에너지 다소비형 산업구조와 소비패턴으로는 온실가스 배출량이 감소할 가능성은 낮은 것으로 분석된다. 따라서 우리나라의 경우 다른 국가에 비하여 기후변화에 취약한 위치에 있고 민감하게 반응함에 따라 미래 기후변화에 대한 영향은 우리나라 농업수자원에 큰 영향을 미칠 것으로 판단된다. 본 연구에서는 기상청에서 제공하는 MM5 기상자료를 이용하여 농업용저수지 필요저수량 변화를 예측하였다. MM5 기상자료는 충남 서산관측소 과거 관측자료를 이용하여 편의보정을 거쳐 재추출하였다. 생성된 자료는 물수지분석 입력 자료로 구축하여 충남에 위치한 고풍저수지에 대하여 필요저수량변화를 예측하였다. 그 결과 기온상승으로 인한 실재증발산량은 676mm에서 717mm로 41mm가 증가하였으며, 소비수량 또한 1,617mm에서 1,659mm로 42mm 증가하였다. 유효우량은 2020s는 520mm 이였으나 2080s는 533mm으로 13mm 증가한 것으로 분석되었다. 본 자료를 이용하여 고풍저수지의 필요저수량을 분석한 결과 2020s, 2050s, 2080s 각각 31.2%(3,538.9천$m^3$), 16.0%(1,489.7천$m^3$), 26.6%(2,834.5천$m^3$)가 부족한 것으로 예측되었다. 이는 강우량은 증가하나 기준년도에 비하여 5월 8월이 낮게 예측된 것이 가장 큰 원인으로 분석되었다. 따라서 소비수량은 증가하지만 유효유량의 부족으로 필요저수량이 부족한 것으로 예측되었다.

• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.330-335
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• 1982

A powdered beverage with afruit flavor was stored at 4, 21, 35 and $45^{\circ}C$ for 180 days to study ascerbic acid destruction at the selected temperatures. Degradation of ascorbic acid in the model followed the first order reaction, and the temperature dependence of reaction rate constants at tested temperatures was accounted for by the Arrhenius equqtion. The calculated activation energy for the destruction of ascorbic acid was 3.3 Kcal/mole. The relationship between ascorbic acid content and sensory flavor score of the beverage indicated that samples with destruction of ascorbic acid over 25% showed objectionable flavor. An attempt was made to predict the quality of powdered beverage by using a simulation model. A comparision between ascorbic acid values from shelflife tests and the simulation program showed a good agreement within acceptable error. This result demonstrated that quality of powdered beverage could be predicted by using a computer simulation model with a desired accuracy.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.256-262
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• 1988

During soaking of 4 varieties of Korean soybeans in water at $4-98^{\circ}C$, an equilibrium state was reached after 3 hr at $60-98^{\circ}C$ but no equilibrium state was observed at $4-40^{\circ}C$ during soaking for 10 hrs. The moisture gain of soybeans held a linear relation with the square root of soaking time regardless of soaking temperatures, which indicated that the basic mechanism of water absorption was diffusion of water. The log time to reach a fixed moisture content showed a linear relation with the soaking temperature during soaking of soybeans at $4-60^{\circ}C$. The z-value decreased in proportions to the increase of hydration. The z-value to reach 50% hydration was the same in all soybeans.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.390-396
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• 1998

Neutral stream was generated from Helicon plasma source and was applied to etch silicon for the purpose of preventing physical and electrical damages from the bombardment of charged particles with high translation energy. By installing a permanent magnet and applying positive bias beneath the substrate, the cusp-magnetic and electric fiddles were generated in order to remove the charged particles from the downstream plasma. As a result, the electron density and ion density in the vicinity of the substrate were reduced by 1/1000 and 1/10, respectively. The directional etching of silicon was observed and the etch rate was found to be very low to below 100 $\AA$/min at a pressure of $8.5{\times}10^{-4}$ Torr, when $Cl_2$ and 10% $SF_{sigma}$ etchant gases were used.

• Membrane Journal
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• v.6 no.1
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• pp.44-52
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• 1996

For the purpose of the optimal design of a frame and plate type of pervaporation module, model equations which can predict the effects of feed flow condition on the temperature distribution of the feed developed in the module were established and the temperature distribution with feed flow condition was investigated through the model si$$\mu$ation. With increasing the Reynolds number of feed flow in the module, the flow velocity gradient in the channel height-direction as well as the volume rate of feed which acts as energy source for the evaporation of perrneants on the permeate-side surface of a membrane increased to such an extent that both mass and heat flux in the channel height direction could increase and the temperature drop of feed due to the evaporation of the permeant could be reduced correspondingly. A decrease in channel height caused the temperature drop of feed because of decreasing feed flow in the module. It was observed that the si$$\mu$ation result on the effect of Re on the temperature distribution of feed in the module has an agreement with experiment.