• JSTS:Journal of Semiconductor Technology and Science
• /
• 제16권2호
• /
• pp.251-254
• /
• 2016

An energy-efficient object matching accelerator is proposed for mobile object recognition based on matching prediction scheme. Conventionally, vocabulary tree has been used to save the external memory bandwidth in object matching process but involved massive internal memory transactions to examine each object in a database. In this paper, a novel object matching accelerator is proposed based on matching predictions to reduce unnecessary internal memory transactions by mitigating non-target object examinations, thereby improving the energy-efficiency. Experimental results show a 26% reduction in power-delay product compared to the prior art.

• 센서학회지
• /
• 제27권6호
• /
• pp.374-379
• /
• 2018

The piezocomposite transducer is widely used because it is highly efficient in transforming electric energy into mechanical energy, and its frequency range is broader than that of other types of ultrasound transducers. A general piezocomposite transducer is composed of an acoustic lens, impedance matching layers, piezoelectric materials, and backing layers. When an input voltage is applied to a piezoelectric material as an active material, it generates sound waves while vibrating. At that time, an impedance matching layer helps the sound waves to propagate forward while reducing the impedance mismatch that may occur at the interface between the active material and its front material. The impedance mismatch has a negative effect on the signal of an ultrasound transducer; thus, it is important to design a matching layer to overcome the issue. In this study, an optimized feature of a matching layer with gradient properties is studied. An objective function is defined to minimize both the average and the deviation of the reflection coefficients that are functions of the frequencies. As a result, an improvement in the signal characteristics with respect to the sensitivity and bandwidth is reported.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권11호
• /
• pp.5203-5217
• /
• 2018

In order to increase the capacity and improve the spectrum efficiency of wireless communication systems, this paper proposes a rate-based two-sided many-to-one matching game algorithm for energy-harvesting small cells with non-orthogonal multiple access (NOMA) in heterogeneous cellular networks (HCN). First, we use a heuristic clustering based channel allocation algorithm to assign channels to small cells and manage the interference. Then, aiming at addressing the user access problem, this issue is modeled as a many-to-one matching game with the rate as its utility. Finally, considering externality in the matching game, we propose an algorithm that involves swap-matchings to find the optimal matching and to prove its stability. Simulation results show that this algorithm outperforms the comparing algorithm in efficiency and rate, in addition to improving the spectrum efficiency.

• 한국음향학회지
• /
• 제22권2호
• /
• pp.96-103
• /
• 2003

본 논문은 매칭 퍼슈잇 (Matching Pursuit)에 인지적인 가중치를 사용하여 오디오 신호를 정현파 모델링하는 것에 대해 기술한다. 매칭 퍼슈잇은 입력 신호에서 에너지가 가장 큰 성분들을 반복적으로 추출해 원 신호와 재생 신호의 차이가 영에 도달될 때까지 계속된다. 본 논문에서는 매칭 퍼슈잇에 심리음향모델을 사용한 인지적인 매칭 퍼슈잇으로 입력 신호로부터 인지적으로 중요한 성분을 차례대로 추출하였다 인지적인 매칭 퍼슈잇의 성능을 평가하기 위해 인지적인 가중치를 주지 않은 정현파 매칭 퍼슈잇과 비교 평가하였다. 여러 가지 입력 신호에 대한 실험 결과 정현파 매칭 퍼슈잇보다 인지적인 매칭 퍼슈잇의 성능이 좋았고, 특히 시간축 변화율이 큰 신호일 경우에 인지적인 매칭 퍼슈잇을 통해 원래 신호의 음질을 더 잘 복원할 수 있었음을 확인하였다.

• 전기학회논문지
• /
• 제68권2호
• /
• pp.304-309
• /
• 2019

This paper presents a CMOS RF-to-DC converter for video surveillance disposable IoT applications. It widely harvests RF energy of 3G/4G cellular low-band frequency range by employing a tunable impedance matching network. The proposed converter consists of the differential-drive cross-coupled rectifier and the matching network with a 4-bit capacitor array. The proposed converter is designed using 130-nm standard CMOS process. The designed energy harvester can rectify the RF signals from 700 MHz to 900 MHz. It has a peak RF-to-DC conversion efficiency of 72.25%, 64.97%, and 66.28% at 700 MHz, 800 MHz, and 900 MHz with a load resistance of 10kΩ, respectively.

• 전자공학회논문지B
• /
• 제30B권6호
• /
• pp.59-66
• /
• 1993

Stereo vision is useful in obtaining three dimensional depth information from two images taken from different view points. Neural network modeling for stereo matching, the key step in stereo vision, is defined by an energy function satisfying with three constraints proposed by Marr and Poggio. Stereo matching is then carried out through the network to find minimum energy corresponding to the optimized solution of the problem. An algorithm for stereo matching using an analog neural network is presented here. The network can reduce errors in initial state an early iteration steps by adoption of continuous sigmoid function in stead of binary state. The experimental results show good matching performance for sparse random dot stereogram and real image.

• 한국태양에너지학회 논문집
• /
• 제38권4호
• /
• pp.55-66
• /
• 2018

nZEH (net-Zero Energy House) is defined as a self-sufficient energy building where the sum of energy output generated from new & renewable energy system and annual energy consumption is zero. The electricity generated by new & renewable energy system with the form of distributed generation is preferentially supplied to electrical demand, and surplus electricity is transmitted back to grid. Due to the recent expansion of houses with photovoltaic system and the nZEH mandatory by 2025, the rapid increase of distributed generation is expected. Which means, we must prepare for an electricity-power accident and stable electricity supply. Also electricity charges have to be reduce and the grid-connected should be operated efficiently. The introduction of ESS is suggested as a solution, so the analysis of the load matching and grid interaction is required to optimize ESS design. This study analyzed the load matching and grid interaction by expected consumption behavior using actual data measured in one-minute intervals. The experiment was conducted in three nZEH with photovoltaic system, called all-electric houses. LCF (Load Cover Factor), SCF (Supply Cover Factor) and $f_{grid}$ (Grid Interaction Index) were evaluated as an analysis indicator. As a result, LCF, SCF and $f_{grid}$ of A house were 0.25, 0.23 and 0.27 respectively; That of B house were 0.23, 0.23, 0.19, and that of C were 0.20, 0.19, 0.27 respectively.

• 에너지공학
• /
• 제25권1호
• /
• pp.131-144
• /
• 2016

최근 기후변화로 인해 전 세계적인 지구온난화 피해가 심각해지면서 주요원인인 온실가스에 대한 배출 규제가 확대되고 있다. 그 중 온실가스 배출량의 약 25%를 차지하는 건물분야에 대해 정부에서는 2020년까지 BAU 대비 26.9%까지 감축하겠다는 목표를 발표하였다. 이를 달성하기 위해 건물부문의 에너지 수요를 원천적으로 저감하는 녹색건축물 활성화 방안을 추진하고 있다. 하지만 녹색건축물 활성화의 상세 이행계획 수립 및 관리, 그리고 시행에 따른 효과를 분석하기 위해서는 건물 에너지 사용량에 대한 데이터 및 관련 통계 자료가 필수적이다. 이를 위해 정부는 전국 680만동의 건물에서 사용되는 에너지 정보를 통합 관리할 수 있는 국가 건물에너지 통합관리시스템을 구축하였다. 하지만 현재 구축된 국가 건물에너지 통합관리시스템의 Database는 건축물대장 정보와 공급기관의 에너지정보를 매칭해서 사용하기 때문에 수동으로 작업이 이루어지고 있으며, 이로 인해 많은 문제들이 발생한다. 따라서 Database의 신뢰성을 확보하기 위해서는 지속적인 고도화 작업이 이루어져야 한다. 본 과제는 현재 가동 중인 국가 건물에너지 통합관리시스템의 Database를 분석하여, 시스템의 한계 및 개선방안 도출하고, 이를 통해 데이터의 신뢰성 확보 및 활용성을 증대 시키고자 하였다. 구축된 Database 분석 결과 건축물 정보와 에너지정보가 매칭된 유효데이터는 평균 85.6%이고, 미매칭된 데이터는 평균 14.4%로 나타났다. 미매칭된 데이터는 다시 건물 특성에 따른 미매칭 유형을 분석하였으며, 그 결과 건축물 정보가 없는 경우가 전체의 58.2%에 달했다. 따라서 향후 신규 구축 data의 매칭 작업 용이성 및 현재 Database에 대한 정확성 확보하기 위해서는 건축물 정보와 에너지정보 간의 주소 표준화 및 속성정보 체계를 마련할 필요가 있다. 또한 비도시지역 및 영세한 주거지역에서 사용비중이 높은 석유류 에너지원 및 향후 발전 가능성 및 활용 가능성이 높은 신재생 에너지와 같이 다른 에너지원에 대한 정보를 포함시킬 수 있도록 시스템 구축이 필요할 것으로 사료된다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 추계학술대회논문집
• /
• pp.506-509
• /
• 2006

Shaped Sound Focusing is defined as the generation of acoustically bright shape in space using multiple sources. The acoustically bright shape is a spatially focused region with relatively high acoustic potential energy level. In view of the energy transfer, acoustical focusing is essential because acoustic energy is very small to use other type of energy. Practically, focused sound shape control not a point is meaningful because there are so many needs to enlarge the focal region especially in clinical uses and others. If focused sound shape can be controlled, it offers various kinds of solutions for clinical uses and others because a regional focusing is essentially needed to reduce a treatment time and enhance the performance of transducers. For making the shaped-sound field, control variables, such as a number of sources, excitation frequency, source positioning, etc., should be taken according to geometrical sound shape. To verify these relations between them, wavenumber domain matching method is suggested because wavenumber spectrum can provide the information of control variables of sources. In this paper, the procedures of shaped sound focusing using wavenumber domain matching and relations between control variables and geometrical sound shape are covered in case of an acoustical ring.

• 신재생에너지
• /
• 제19권3호
• /
• pp.1-12
• /
• 2023

This study aims to evaluate the optimal size of the hydrogen facility to be installed in a zero-energy district in terms of load matching and facility efficiency. A mismatch between energy generation and consumption is a common occurrence in zero-energy districts. This mismatch adversely effects the energy grid. However, using an energy carrier such as hydrogen can solve this problem. To determine the optimal size of hydrogen fuel cells to be used on-site, simulation of hydrogen installation is required at both district-and building- levels. Each case had four operating schedules. Therefore, we evaluated eight scenarios in terms of load matching, heat loss, and facility operational efficiency. The results indicate that district-level installation of hydrogen facilities enables more efficient energy use. Additionally, based on the proposed model, we can calculate the optimal size of the hydrogen facility.