• International Journal of Computer Science & Network Security
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• 제24권2호
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• pp.53-58
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• 2024

This paper presents a novel miniaturized 3-D cubic antenna for use in wireless sensor network (WSN) application. The geometry of this antenna is designed as a cube including a meander dipole antenna. A truly omnidirectional pattern is produced by this antenna in both E-plane and H-plane, which allows for non-intermittent communication that is orientation independent. The operating frequency lies in the ISM band (centered in 2.45 GHz). The dimensions of this ultra-compact cubic antenna are 1.25*1.12*1cm3 which features a length dimension λ/11. The coefficient which presents the overall antenna structure is Ka=0.44. The cubic shape of the antenna is allowing for smart packaging, as sensor equipment may be easily integrated into the cube hallow interior. The major constraint of WSN is the energy consumption. The power consumption of radio communication unit is relatively high. So it is necessary to design an antenna which improves the energy efficiency. The parameters considered in this work are the resonant frequency, return loss, efficiency, bandwidth, radiation pattern, gain and the electromagnetic field of the proposed antenna. The specificity of this geometry is that its size is relatively small with an excellent gain and efficiency compared to previously structures (reported in the literature). All results of the simulations were performed by CST Microwave Studio simulation software and validated with HFSS. We used Advanced Design System (ADS) to validate the equivalent scheme of our conception. Input here the part of summary.

• 센서학회지
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• 제31권3호
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• pp.180-186
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• 2022

Photosynthetically active radiation flux density (PPFD) and daily light integral (DLI) values related to plant photosynthesis were obtained using the sunlight time and insolation data points in the agricultural weather sensor data for Jinan-gun, Jeollabuk-do, Korea from 2016 to 2020. The objective was to optimize the photo-environmental conditions for cultivating ginseng. The range of average monthly sunshine duration was 395.5-664.1 min, with the longest duration observed in June. The range of average annual accumulated daily insolation was 11.98-17.65 MJ·m^-2. The range of average daily external DLI calculated from the insolation and solar time data was 22.3-36.1 mol·m^-2·d^-1, and the annual cumulative DLI was 8,156-13,175 mol·m^-2·d^-1. Both the insolation and DLI values were the highest in 2016 and lowest in 2020. Based on the PPFD required for ginseng growth (111-185 µmol·m^-2·s^-1), the monthly average daily DLI and monthly cumulative DLI were 3.51-5.87 and 82-228 mol·m^-2·d^-1, respectively. The range of five-year average value for the external monthly cumulative DLI was 298-1,459 mol·m^-2·d^-1, and the monthly cumulative DLI values when a black double shading film and blue-white shading film were applied were 101-496 and 36-175 mol·m^-2·d^-1, respectively. A comparative analysis of DLI values indicated that shading was required to ginseng growth throughout the year under natural light. When the black double shading film was used, shading was required from March to October. When the blue-white shading film was applied from April to August, (i.e., the period with active ginseng growth) the appropriate DLI for ginseng growth could be continuously maintained. Regional weather differences due to climate change are gradually increasing, and even in one region, monthly and cumulative DLI values are different every year. Therefore, in order to implement a precise agricultural environment for ginseng cultivation, precise analysis and continuous research using agricultural weather sensor big data is required.

• 대한방사선치료학회지
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• 제17권2호
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• pp.125-131
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• 2005

목 적 : 폐암 환자 중 호흡에 의한 종양의 움직임이 큰 폐 하엽에서 정위적 방사선수술 시 호흡에 의한 종양의 움직임을 감소시키는 방법으로 종양의 움직임이 적은 호흡 주기에서만 방사선을 조사할 수 있는 respiratory gating system을 사용함으로써 그 유용성에 대하여 알아보고자 한다. 대상 및 방법 : 폐 하엽의 정위적 방사선 수술 환자 2명을 대상으로 하였으며, 환자의 복부에 maker block (sensor)을 부착하고 tracking camera와 Real Time Position Management (RPM)를 이용하여 호흡 주기를 측정하면서 1회 호흡주기에서 10 phases로 4D-CT를 촬영하였다. 종양의 위치 변화가 급격하지 않은 호흡주기 (%)의 phases를 치료 phases로 결정하였고, 치료 phases의 CT image를 Maximum Intensity Projection (MIP) 기법으로 재구성 후 volume contouring을 하였다. Set up의 재현성 및 GTV의 위치 변화를 확인하기 위해 치료 전과 치료 중 2회의 4D-CT 촬영을 하였다. 결 과 : GTV의 움직임이 가장 큰 Y(longitudinal)축에서 A환자는 전체 호흡주기($0{\sim}90%$)에서 9.4 mm가 치료 호흡 주기 범위 ($30{\sim}60%$)에서는 2.6 mm로, B환자는 전체 호흡주기 ($0{\sim}90%$)에서 11.7 mm가 치료 호흡주기의 범위($30{\sim}70%$)에서는 2.3 mm로 감소하였다. 2회의 4D-CT 비교 결과 set up의 X, Y, Z축 오차는 모두 3 mm이내였다. 결 론 : 호흡에 의한 종양의 움직임이 큰 폐 하엽에서 정위적 방사선수술 시행 시 respiratory gating system의 사용은 종양의 움직임을 5 mm이내로 감소시킬 수 있어 유용하였다.

• 한국통신학회논문지
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• 제21권1호
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• pp.47-58
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• 1996

An object color can be seen differently under the various outer illuminants. However, human visual system has color constnacy that the object color can be seen constantly under the different outer illuminants. When the viewer watches TV under specific that the object color can be seen constantly under the different outer illuminants. When the viewer bathes TV under specific outer illuminants, he perceives distortes color due to the emitting specturm of outer illuminants as well as the radiation of CPT itself. Namely, when the outer illuminants such as fluorescent and incandescent lamps incident on CPT, brightness, saturation, hue, itself. Namely, when the outer iluminants such as fluorescent and incandescent lamps incident on CPT, brightness, saturation, hue, and contrast on color pictures are changend, he perceives distortedcolr fromthe original color. In this paper color enhancement algorithm based on light intensity and outer light decision funtion using RGB sensor was proposed. The implemented TV of proposed algorithm has higher visual quality at the view point of human visual system and more vivid than that ofcoventional color TV.

• 정보통신설비학회논문지
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• 제11권2호
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• pp.39-45
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• 2012

In recent years the USN(Ubiquitous Sensor Networks) technology has been applied in the greenhouse in order to control temperature and humidity automatically. In this paper, we proposed a control algorithm using feedback linearization techniques based on a mathematical model for temperature and humidity environment. Especially, Control algorithm is presented to the operation of the ventilator affecting on the temperature and humidity system at the same time. The System has been designed taking into account the disturbance(External temperature, soil temperature, external humidity, solar radiation and wind). In conclusion, I will present a way to control multiple actuator through simulations. The proposed control algorithm is validated using the Matlab/Simulink tools.

• 한국광물학회지
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• 제12권1호
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• pp.1-10
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• 1999

Talc (Mg3Si4O10(OH)2), one of the sheet silicate minerals, which is the hydrothermal alteration product of serpentinite at Cheongarm mine was prepared for the high pressure compressibility studies. Energy dispersive X-ray diffraction experiment was carried out using the Synchrotron Radiation with the Mao-Bell type diamond anvil cell at room temperature. Polycrystalline talc was mixed with MgO powder for pressure sensor as well as pressure medium in the sample chamber. High pressure runs were performed at pressures up to 35.2 GPa. Talc shows no phase transition within the present high pressure region. Bulk modulus of this talc was determined by the Birch-Murnaghan equation of state to be 78 GPa assuming its first pressure derivative Ko' of 4.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.385-387
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• 2005

Polarimetric measurements of the sky radiation by the PSR-I000, which is the multi-spectral polarimeter developed by the Opt Research Corporation and has the same wavelength regions (443nm, 490nm, 565nm, 670nm, 765nm and 865nm) as the ADEOSII/POLDER sensor, have been carried out at the ground station in Kanazawa city, Japan from March to May. First of all, the wavelength dependency of degrees of polarization is examined and it is shown that degrees of polarization measured under the hazy dust cloud are lower than those measured in the clear sky and decrease as the wavelength increases. Next, a new method for estimating optical properties, such as the optical thickness, the number size distribution and the refractive index, of the Asian dust and the ground reflectance from degrees of polarization measured by PSR-I000 is described. Finally, this method is applied to polarization data acquired on April 15,2002. As a result, it is shown that our estimation algorithm provides a good result.

• Journal of information and communication convergence engineering
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• 제6권4호
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• pp.391-395
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• 2008

Wideband terminal and base station is required to serve not only existing 1st and 2nd generation mobile communication systems but also 3rd generation systems. In this paper, we present a feasibility study on coaxial feed compact wideband antenna for UHF RFID reader application. The original antenna was designed for partial discharge detection sensor in high voltage diagnostic system. However, we modified the original prototype to achieve shifted down resonant frequency for wideband wireless communication applications. The experimental result shows good return loss characteristics and radiation patterns except for the total gain at each resonant frequency. The maximum measured gain was 2.45 dBi$\sim$3.18 dBi at 910MHz.

• 센서학회지
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• 제27권5호
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• pp.280-293
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• 2018

The conversion of an invisible thermal radiation pattern of an object into a visible image using infrared (IR) thermal technology is very useful to understand phenomena what we are interested in. Although IR thermal images were originally developed for military and space applications, they are currently employed to determine thermal properties and heat features in various applications, such as the non-destructive evaluation of industrial equipment, power plants, electricity, military or drive-assisted night vision, and medical applications to monitor heat generation or loss. Recently, IR imaging-based monitoring systems have been considered for application in agricultural, including crop care, plant-disease detection, bruise detection of fruits, and the evaluation of fruit maturity. This paper reviews recent progress in the development of IR thermal imaging techniques and suggests possible applications of thermal imaging techniques in agriculture.

• Journal of information and communication convergence engineering
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• 제6권2호
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• pp.164-168
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• 2008

Wideband terminal and base station is required to serve not only existing 1st and 2nd generation mobile communication systems but also 3rd generation systems. In this paper, we presents a feasibility study on single feed compact wideband antenna for wireless communication applications including GSM (890-960 MHz), GPS (1575 MHz), DCS (1710-1880 MHz), PCS (1880-1990 MHz), UMTS (1900-2200 MHz), ISM (2400-2480 MHz), IMT2000 and satellite DMB bands. The original antenna was designed for partial discharge detection sensor in high voltage diagnostic system. However, we modified the original prototype to achieve shifted down resonant frequency for wideband wireless communication applications. The experimental result shows good return loss characteristics and radiation patterns except for the total gain at each resonant frequency. The maximum measured gain was 2.45 dBi${\sim}$3.18 dBi at 1710 MHz${\sim}$1880 MHz.