• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.4
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• pp.247-255
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• 2018

In this work, glucose solution and sodium chloride solution were distinguished noninvasively using a microwave complementary split-ring resonator (CSRR). Based on the electrical properties of the two solutions measured using a open-ended coaxial probe, a CSRR was designed and fabricated for operation at a specific frequency that facilitates differentiating the two solutions. Furthermore, a polydimethylsiloxane mold was fabricated to concentrate the solution at a region where the electric field of the resonator was strongest, and a laminating film was used to prevent contact between the solution and resonator. Experiments were performed by dropping $50{\mu}L$ of the solution in steps of 100 mg/dL up to a maximum human blood glucose level of 400 mg/dL. Our experiments confirmed that the transmission coefficients ($S_{21}$) of glucose solution and sodium chloride solution exhibit variations of -0.06 dB and 0.14 dB, respectively, per 100 mg/dL concentration change at the resonance frequency. Thus, the opposite trends in the variation of $S_{21}$ with change in the concentration of the two solutions can be used to distinguish between them.

• Journal of the Korean Magnetics Society
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• v.27 no.1
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• pp.1-8
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• 2017

Flywheel Energy Storage System (FESS) is composed by flywheel generating rotating potential energy and motor/generator set charging and discharging electric potential energy. The flywheel and motor/generator is connected by rotating shaft. And torque characteristics of motor/generator part can influence charging and mechanical traits of FESS. This paper analyze about motor/generator design method of 5 [kWh] FESS and torque ripple, harmonic effects by change of slots. At First, this paper proposes a method to estimate the flywheel size and the rotor size of the motor from the the rotational kinetic energy by inertia of FESS. The number of induction motor rotor slots for torque ripple reduction in the high speed operation region is selected. This paper performs to reduce the noise and vibration of the flywheel composed of coaxial with motor/generator and flywheel and realize the high efficiency.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.454-454
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• 2014

Silicon microwire array is one of the promising platforms as a means for developing highly efficient solar cells thanks to the enhanced light trapping efficiency. Among the various fabrication methods of microstructures, deep reactive ion etching (DRIE) process has been extensively used in fabrication of high aspect ratio microwire arrays. In this presentation, we show precisely controlled Si microwire arrays by tuning the DRIE process conditions. A periodic microdisk arrays were patterned on 4-inch Si wafer (p-type, $1{\sim}10{\Omega}cm$) using photolithography. After developing the pattern, 150-nm-thick Al was deposited and lifted-off to leave Al microdisk arrays on the starting Si wafer. Periodic Al microdisk arrays (diameter of $2{\mu}m$ and periodic distance of $2{\mu}m$) were used as an etch mask. A DRIE process (Tegal 200) is used for anisotropic deep silicon etching at room temperature. During the process, $SF_6$ and $C_4F_8$ gases were used for the etching and surface passivation, respectively. The length and shape of microwire arrays were controlled by etching time and $SF_6/C_4F_8$ ratio. By adjusting $SF_6/C_4F_8$ gas ratio, the shape of Si microwire can be controlled, resulting in the formation of tapered or vertical microwires. After DRIE process, the residual polymer and etching damage on the surface of the microwires were removed using piranha solution ($H_2SO_4:H_2O_2=4:1$) followed by thermal oxidation ($900^{\circ}C$, 40 min). The oxide layer formed through the thermal oxidation was etched by diluted hydrofluoric acid (1 wt% HF). The surface morphology of a Si microwire arrays was characterized by field-emission scanning electron microscopy (FE-SEM, Hitachi S-4800). Optical reflection measurements were performed over 300~1100 nm wavelengths using a UV-Vis/NIR spectrophotometer (Cary 5000, Agilent) in which a 60 mm integrating sphere (Labsphere) is equipped to account for total light (diffuse and specular) reflected from the samples. The total reflection by the microwire arrays sample was reduced from 20 % to 10 % of the incident light over the visible region when the length of the microwire was increased from $10{\mu}m$ to $30{\mu}m$.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.169-175
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• 2005

The occurrence of tobacco whiteflies, Bemisia tabaci, in greenhouses was monitored in Korea in 2005. Bemisia tabaci occurred in the rose, sweet pepper, tomato, and cucumber greenhouses of Chungbuk, Chungnam, Gyongnam, and Jeonnam Provinces, but not in Jeonbuk and Gyongbuk Provinces. The biotypes and genetic differentiation of the whiteflies collected in each regions were analyzed by mitochondrial 16S DNA sequences. The 16S DNA sequences of Jincheon (Chungbuk Province) samples were similar to DNA data reported from Japan and Israel which were known as the B biotype. However, the DNA sequences of the Buyeo (Chungnam), Geoje (Gyongnam) and Boseong (Jeonnam) collections, which were 100% homologous showed over 99% similarity to the DNA of Q biotype from Spain and Egyrt. Here we report the first founding of the Q biotype in Korea. It is assumed that, unlike the B biotype reported from Jincheon since 1998, the Q biotype might have been introduced recently from the certain foreign region/country to the greenhouses in those provinces.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.136-155
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• 2014

The purpose of this study is to analyze the thermal comfort in Yeongnam area using climatic data and GIS data in order to determine regions necessary to improve thermal environment policies. The results of the calculated PET show that Daegu city is high and Bonghwa-gun is low compared to other regions. PET was compared with the typical classification according to regional characteristics. As a result, PET value of rural areas such as Changnyeong-gun, Haman-gun and Goryeong-gun was high but Green space was too low compared to other rural areas. Yeongnam area was classified according to the value of PET using cluster analysis. As a result, more low grade areas show that green space ratio was low and facility area was high. It is determined that there is a relationship between thermal comfort and land cover. The thermal comfort evaluation map in Yeongnam area will be useful for urban planning in order to establish a sustainable city in climate change.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.529-538
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• 2017

The objectives of this study are to examine and propose a method for establishing a seed story regarding residents of Yongdam 1-dong and to utilize storytelling in establishing town development strategies. Globally, major cities seek urban restoration based on their regional culture and history. Yongdam 1-dong is a downtown area located in Jeju City, South Korea. This study attempts an innovative approach to town-making by storytelling about the residents' lives. The storytelling method may be utilized to establish town development plans in the following ways: 1) To make use of the storytelling method in the town to be introduced in various ways; 2) As an important reference in establishing town development plans; 3) To establish various town-making plans. For example, the method may be used to decide the direction, prepare program contents, plan related festivals, and conduct regional facilitator education programs; and 4) To help experts who participate in voluntary work in the region to understand the town. Using these contents, we can create one of various fields in town development.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.567-578
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• 2022

Various social and environmental problems have recently emerged due to global climate change. In South Korea, coniferous forests in the highlands are decreasing due to climate change whereas the distribution of subtropical species is gradually increasing. This study aims to respond to changes in the distribution of forest species in South Korea due to climate change. This study predicts changes in future suitable areas for Pinus koraiensis, Cryptomeria japonica, and Chamaecyparis obtusa cultivated as timber species based on climate, topography, and environment. Appearance coordinates were collected only for natural forests in consideration of climate suitability in the National Forest Inventory. Future climate data used the SSP scenario by KMA. Species distribution models were ensembled to predict future suitable habitat areas for the base year(2000-2019), near future(2041-2060), and distant future(2081-2100). In the baseline period, the highly suitable habitat for Pinus koraiensis accounted for approximately 13.87% of the country. However, in the distant future(2081-2100), it decreased to approximately 0.11% under SSP5-8.5. For Cryptomeria japonica, the habitat for the base year was approximately 7.08%. It increased to approximately 18.21% under SSP5-8.5 in the distant future. In the case of Chamaecyparis obtusa, the habitat for the base year was approximately 19.32%. It increased to approximately 90.93% under SSP5-8.5 in the distant future. Pinus koraiensis, which had been planted nationwide, gradually moved north due to climate change with suitable habitats in South Korea decreased significantly. After the near future, Pinus koraiensis was not suitable for the afforestation as timber species in South Korea. Chamaecyparis obtusa can be replaced in most areas. In the case of Cryptomeria japonica, it was assessed that it could replace part of the south and central region.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.63-71
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• 2006

There were many theories to suggest the indicators that evaluate stability and reflect the plan in mixed traffic street in all traffic modes This Paper analyzed residential street of Suwon City adopting time-space occupancy index among these indicates. Three survey street. congregated into apartment house. were selected to analyze this and pictured by video camera over one hour. and the length of these street were 76m, 55m, and 34m each, and major street by each region, comparably high in Pedestrians and pass vehicles, were selected. Basic datum to calculate time-space occupancy index and time-space occupancy index per person was gathered through video analysis. i.e Parameters for pedestrians, cars, bicycles, average speed of bicycles, and parking car. There are some limitation to analyze LOS of mixed traffic street in all traffic modes, not pedestrian mall. Therefore this paper presented evaluation standard of LOS. In conclusion. the aim of this paper is to suggest modeling based on guidelines for evaluating LOS of mixed traffic street in all traffic modes. It is estimated that this will be influencing indicates for improving pedestrian environment, and Planning mixed traffic street in future.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.579-591
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• 1999

The operation of a reservoir system is necessary for establishing the operation rule as well as designing the reservoirs for water resources planning or management. Increasingly complex water resource systems require more advanced operation techniques. As a result, various techniques have been introduced and applied until now. In this study Linear Tracking model based on optimal control theory is applied to the operation of the largest scale multi-reservoir system in the Han river and its applicability proved. This system normally supplies the water resources required downstream for hydro-power and plays a role in satisfying the water demand of the Capital region. For the optimal use of the water resources the Linear Tracking model is designed with the objective to maximize the hydro-power energy subject to the water supply demand. The multi-reservoir system includes the seven main reservoirs in IIan river such as Hwachon, Soyanggang, Chunchon, Uiam, Cheongpyong, Chungju and Paldang. These reservoirs have been monthly operated for the past 21 years. Operation results are analyzed with respect to both hydro"power energy and water supply. Additionally the efficiency of the technique is assessed.sessed.

• Journal of the Korean Geographical Society
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• v.50 no.3
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• pp.255-276
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• 2015

This paper presents a multi-agent system model of land-use and cover changes, which is developed and applied to the Gariwang-san and its vicinity, located in Pyeongchang and Jeongseon-gun, Gangwon province, Korea. The Land Use Dynamics Simulator (LUDAS) framework of this study is well suited for representing the spatial heterogeneity and dynamic interactions between human and natural environment, and capturing the impacts of forest-opening policy interventions to future socio-economic and natural environment changes. The model consists of four components: (1) a system of human population, (2) a system of landscape environment, (3) decision-making procedures integrating human(or household), environmental and policy information into forest land-use decisions, and (4) a set of policy scenarios that are related to the forest-opening. The results of model simulation by different combination of various forest management scenarios are assessed by the levels of household income, ecosystem service value and income inequality in the study region. As a result, the optimal scenario of forest-opening policies in the study region is to open the forest to local residential community for the purpose of recreation, considering the distinctive topographical feature. The model developed in this research is expected to contribute to a decision support system for sustainable forest management and various land-use policies in Korea.