• 전기학회논문지
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• 제58권12호
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• pp.2462-2467
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• 2009

This paper proposes a dual band branch line coupler (BLC) using a composite right/left handed (CRLH) transmission line. The existing dual band BLCs with open stubs require hundreds of line impedance for the open stub as the frequency bands approach to each other, so it has been almost impossible to realize them. However in the proposed BLC, a CRLH transmission line replaces the open stub with an extremely high line impedance so that the BLC circuit may be realized even two frequencies are close to each other. As an example, a dual band BLC operating at 1800MHz and 2300MHz (the frequency ratio is 1:1.28) is designed and measured. Open stubs with $560\Omega$ line impedance are replaced by CRLH transmission lines for realizing the dual band BLC. The measured performances prove that the dual band operation is well acceptable and the proposed design method is successful even the ratio between two frequencies is not around two nor more.

• 한국전자파학회논문지
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• 제13권7호
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• pp.633-640
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• 2002

본 논문에서는 이중공진 칩 meander 안테나를 제안하였다. 제안된 안테나는 기존 meander 안테나의 소형화 특성을 유지하면서 인접한 주파수에서 이중공진하는 특징을 갖는다. LTCC-MLC 공정을 이용하여 제작하였고, 2.20 GHz와 2.883 GHz에서 이중공진(주파수비=1.35)하며, meander 패치의 크기는 15.7 mm $\times$ 6.52 mm( 0.32 λg $\times$ 0.133 λg)이다. 그리고 이중공진 meander 안테나의 추가적인 소형화를 위해 3차원 구조를 제안한다. 이 3차원 구조를 이용하여 약 50 %의 크기를 추가적으로 소형화하였다. 전류분포를 통해 제안된 안테나가 이중공진하는 원리를 확인하였고, 제작된 안테나의 반사손실 및 방사패턴의 특성을 분석하였다.

• 조명전기설비학회논문지
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• 제28권4호
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• pp.80-87
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• 2014

This paper suggests the dual-gap for generating power and increasing the torque of a direct-drive permanent magnet synchronous motor in a hybrid-cycle. To consider easy coil winding, we applied a structure of dual-gap for the permanent magnet synchronous motor (PMSM). Because the torque of PMSM with the dual-gap is very large, we are designed the appropriate specifications of the PMSM by selected the appropriate dual-gap slot and poles combination. The prototype model is selected by design theory for increasing torque and maximizing output power of PMSM. And the detailed structure design of the model was designed by the loading distribution method. The PMSM models were analyzed by finite element method. Finally, we have suggested appropriate rotor structure has benefit to further increasing torque and prevent decreasing of the output power in PMSM with dual-gap.

• 태양에너지
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• 제18권4호
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• pp.11-22
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• 1998

Floor panel heating system using hot water is the primary heating system of domestic residential building. This paper presents the results of performance analysis of the heat pump system with air source evaporator and single unit dual sink(SUDSk) condenser. The heat exchanger combines two separated condensers into a single condenser and the object of the SUDSk condenser is to release energy to dual sinks, i.e. air for air heating system and water for panel heating system in one single unit. Simulation program is developed for single unit dual source(SUDS) SUDSk heat pump system and some experimental data are obtained and compared with simulation results. Differences of heating capacity and COP in dual source operating mode are 7% and 8% respectively. Simulation results are in good agreement with test results. Therefore, developed program is effectively used for design and performance prediction of dual source dual sink heat pump system with SUDS evaporator and SUDSk condenser.

• 전기학회논문지
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• 제61권9호
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• pp.1260-1268
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• 2012

Recently, lack of power reserve margin was observed quite often. In this paper, we studied the method to secure power source for a short time, to cut the utility power peak load, and to reduce the users electricity bills. Emergency diesel generator of an office building is to be converted into a dual-fuel engine generator which is responsible for a portion of the peak load. Compared to the conventional diesel fuel generator, the proposed dual-fuel engine is able to reduce the generation power cost by dual-fuel combustion, and it also mitigates the building's utility power peak load by charging the building's peak load. If the dead resources (a group of emergency dual-fuel engine generators), as a Virtual Power Plant, are operating in peak time, we can significantly reduce future large power development costs. We investigated the current general purpose electricity bills as well as the records of the building electric power usage, and calculated diesel engine generator renovation costs, generation fuel costs, driving conditions, and savings in electricity bills. The proposed dual-fuel engine generation method reduces 18.1% of utility power peak load, and turned out to be highly attractive investment alternative which shows more than 27% of IRR, 76 million won of NPV, and 20~53 months of payback periods. The results of this study are expected to be useful to developing the policy & strategy of the energy department.

• 전기학회논문지
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• 제59권11호
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• pp.2032-2037
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• 2010

This paper describes a design of dual band amplifier using left handed (LHJ) transmission line, which is a part of composite right/left handed (CRLH) transmission line. It is well known that CRLH transmission lines show dual band frequency response. At first, two single-band amplifiers for frequency f1 and f2 are designed, and their matching networks at both amplifiers are synthesized into the dual band matching network by adopting CRLH structure. As an example for proving the validity of the proposed design, a dual band amplifier operating at 1800MHz and 2300MHz is designed, fabricated and measured. The simulation and measurement show that the proposed amplifier operates well at the desired dual bands with the gain of 13.65dB and 19dB at 1850MHz and 2360MHz, respectively, and a good matching performances. In addition, a quite good agreement between the simulation and measurement is observed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.320-323
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• 2010

본 논문은 작은 사이즈가 요구되는 제한적인 모바일 환경의 프로세서에서 별도의 연산기 없이 제안된 Dual Phase 명령어 구조를 이용해 효율적인 로그와 지수 연산이 가능한 방법을 제안한다. Floating Point 자료형의 지수부와 실수부를 추출하는 명령어 세트와 테일러 급수 전개를 이용해 로그의 근사치를 계산하여 24비트 단정도 부동 소수점을 연산하고, Dual Phase 명령어 구조를 활용해 명령어 실행 사이클을 줄였다. 제안된 구조는 별도의 연산기를 두는 구조보다 작은 사이즈를 유지하면서 성능저하를 33%까지 최소화 할 수 있는 구조이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권10호
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• pp.3554-3570
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• 2021

With the rapid development of the Chinese water project, the safety monitoring of dams is urgently needed. Many drawbacks exist in dams, such as high monitoring costs, a limited equipment service life, long-term monitoring difficulties. MEMS sensors have the advantages of low cost, high precision, easy installation, and simplicity, so they have broad application prospects in engineering measurements. This paper designs intelligent monitoring based on the collaborative measurement of dual MEMS sensors. The system first determines the endpoint coordinates of the sensor array by the coordinate transformation relationship in the monitoring system and then obtains the dam settlement according to the endpoint coordinates. Next, this paper proposes a dual-MEMS sensor collaborative measurement algorithm that builds a mathematical model of the dual-sensor measurement. The monitoring system realizes mutual compensation between sensor measurement data by calculating the motion constraint matrix between the two sensors. Compared with the single-sensor measurement, the dual-sensor measurement algorithm is more accurate and can improve the reliability of long-term monitoring data. Finally, the experimental results show that the dam subsidence monitoring system proposed in this paper fully meets the engineering monitoring accuracy needs, and the dual-sensor collaborative measurement system is more stable than the single-sensor monitoring system.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2371-2376
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• 2021

As the γ-ray energy increases, a reconstructed image becomes noisy and blurred due to the penetration of the γ-ray through the coded mask. Therefore, the thickness of the coded mask was increased for high energy regions, resulting in severely decreased the performance of the detection efficiency due to self-collimation by the mask. In order to overcome the limitation, a modified uniformly redundant array γ-ray imaging system using dual anti-mask method was developed, and its performance was compared and evaluated in high-energy radiation region. In the dual anti-mask method, the two shadow images, including the subtraction of background events, can simultaneously contribute to the reconstructed image. Moreover, the reconstructed images using each shadow image were integrated using a hybrid update maximum likelihood expectation maximization (h-MLEM). Using the quantitative evaluation method, the performance of the dual anti-mask method was compared with the previously developed collimation methods. As the shadow image which was subtracted the background events leads to a higher-quality reconstructed image, the reconstructed image of the dual anti-mask method showed high performance among the three collimation methods. Finally, the quantitative evaluation method proves that the performance of the dual anti-mask method was better than that of the previously reconstruction methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.2078-2093
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• 2019

Visual smoke recognition is a challenging task due to large variations in shape, texture and color of smoke. To improve performance, we propose a novel smoke recognition method by combining dual-encoded features that are extracted from both spatial and Curvelet domains. A Curvelet transform is used to filter an image to generate fifty sub-images of Curvelet coefficients. Then we extract Local Binary Pattern (LBP) maps from these coefficient maps and aggregate histograms of these LBP maps to produce a histogram map. Afterwards, we encode the histogram map again to generate Dual-encoded Local Binary Patterns (Dual-LBP). Histograms of Dual-LBPs from Curvelet domain and Completed Local Binary Patterns (CLBP) from spatial domain are concatenated to form the feature for smoke recognition. Finally, we adopt Gaussian Kernel Optimization (GKO) algorithm to search the optimal kernel parameters of Support Vector Machine (SVM) for further improvement of classification accuracy. Experimental results demonstrate that our method can extract effective and reasonable features of smoke images, and achieve good classification accuracy.