• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3365-3370
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• 2007

We developed micro power generation system using piezoelectric materials. In our system, the ambient vibrating energy is converting to electric energy by deflection of piezoelectric beams. The system consists of energy generating parts, converting enhancement parts, electric regulation and charging parts, and interface with small-energy-consuming mobile devices. The geometry of piezoelectric beams, the source of vibrating energy, and the electric load of target application determine the characteristics of generating electric power, such as impedance, voltage, current and power density. Therefore, we made a model for analysis of generating power with given information such as piezoelectric materials, geometry, vibration type, and mass. With this model, we can calculate capacitance of piezoelectric beams, generating voltage, current, and power. To obtain maximum energy transfer efficiency, we approached this study in the view of material, electrical, and mechanical engineering

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.263-263
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• 2007

In the future, self-contained sensors and processing units will need on-board, renewable power supplies to be truly autonomous. One way of supplying such power is through energy harvesting, processes by which ambient forms of energy are converted into electricity. One energy harvesting technique involves converting kinetic energy, in the form of vibrations, into electrical energy through the use of piezoelectric materials. Researchers are currently investigating how piezoelectric materials can be used to harvest power. This study examines the use of auxiliary structures, consisting of a mechanical fixture and a lead zirconate/lead titanate (PZT) piezoelectric element, which can be attached to any boundary conditions vibrating beam of the any boundary conditions. Adjusting various boundary conditions of these structures can maximize the strain induced in the attached PZT element and improve power output.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.4
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• pp.158-164
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• 2016

Currently, identifying a new carbon-free energy resource is important in order to resolve the global warming problem. Along the same line, this paper studied how to convert magnetic force into mechanical force and a new basic mechanism of converting magnetic force into mechanical force was identified. Long-term reliability test, around 15 million times, was also conducted at $-1^{\circ}C{\sim}27^{\circ}C$ to evaluate the durability of magnetic force. As a result, tests showed that the deviation of the mechanical force was within 0.8% of the initial force, and the relation between repulsive force (P) and ambient temperature (T) was formulated in a linear equation P = -0.175T+78.945.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.571-574
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• 2012

optical wavelength analyzer design and implementation of this study is about. For experiments, the input light in the infrared, ultraviolet, visible as a light source was used. I-V Converting circuit configured as a photodiode. I-V Converting circuit voltage is measured. Measured voltage can be determined for a wavelength in size.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.87-96
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• 2011

According to adverse effects of ecosystems due to a bulk of fossil fuel consumption, utilization of sustainable and renewable energy is required. In this paper, converting the energy crisis into an opportunity of new growth is expected by converting heat energy in asphalt pavement into electric power using thermoelectric effect. For this, experiments of inserting heat collector pipe and thermoelectric element into asphalt were performed, and the electric power of heat energy harvesting was measured for development of efficient harvesting system of heat energy. As the results of experiments, electric conversion of average 19.86W per day is possible at $1m^2$ conversion area at a depth of 5cm, and possibility of this system was confirmed. Consequently, a systematic "Green Road" using sustainable heat energy source in asphalt pavement simultaneously with environmental maintenance and econovic growth was suggested.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.319-324
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• 2012

This paper presents the study of 3-Phase bi-directional DC to AC inverter with unity power factor. 3-Phase bi-directional DC to AC inverter is important for the bi-modal PV PCS with an energy storage system. Both Inverting and converting are needed to connect between the grid side and boost converting side to charge and discharge the energy storage system. The paper proposes the appropriate circuit topology and proper control system for the bi-directional inverter. It also proposes the method of selecting the optimum control method considering system stability. PSIM simulation is used to validate the proposed algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.1
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• pp.69-76
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• 2010

The segmentation of moving object in video sequence is a core technique of intelligent image processing system such as video surveillance, traffic monitoring and human tracking. A typical method to segment a moving region from the background is the background subtraction. The steps of background subtraction involve calculating a reference image, subtracting new frame from reference image and then thresholding the subtracted result. One of famous background modeling is Gaussian mixture model (GMM). Even though the method is known efficient and exact, GMM suffers from a problem that includes false pixels in ROI (region of interest), specifically shadow pixels. These false pixels cause fail of the post-processing tasks such as tracking and object recognition. This paper presents a method for removing false pixels included in ROT. First, we subdivide a ROI by using shape characteristics of detected objects. Then, a method is proposed to classify pixels from using histogram characteristic and comparing difference of energy that converts the color value of pixel into grayscale value, in order to estimate whether the pixels belong to moving object area or shadow area. The method is applied to real video sequence and the performance is verified.

• Ocean Systems Engineering
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• v.8 no.2
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• pp.119-166
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• 2018

The assessment of the potential for the design of marine renewable energy systems is reviewed and the current situation for marine renewable energy is promising. The most studied forms of marine renewable energy are ocean wind energy, ocean wave energy and tidal energy. Wind turbine generators include mostly horizontal axis type and vertical axis type. But also more exotic ideas such as a kite design. Wave energy devices consist of designs converting wave oscillations in electric power via a power take off equipment. Such equipment can take multiple forms to be more efficient. Nevertheless, the technology alone cannot be the only step towards marine renewable energy. Many other steps must be overcome: policy, environment, manpower as well as consumption habits. After reviewing the current conditions of marine renewable energy development, the authors analyzed the key factors for developing a strong marine renewable energy industry and pointed out the huge potential of marine renewable energy.

• BMB Reports
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• v.31 no.5
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• pp.459-467
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• 1998

A new set of functional group interaction energy descriptors relevant to the ACE (Angiotensin-Converting Enzyme) inhibitory peptide, QSAR (Quantitative Structure Activity Relationships), is presented. The functional group interaction energies approximate the charged interactions and distances between functional groups in molecules. The effective energies of the computationally derived geometries are useful parameters for deriving 3D-QSAR models, especially in the absence of experimentally known active site conformation. ACE is a regulatory zinc protease in the renin-angiotensin system. Therapeutic inhibition of this enzyme has proven to be a very effective treatment for the management of hypertension. The non bond interaction energy values among functional groups of six-feature of ACE inhibitory peptides were used as descriptor terms and analyzed for multivariate correlation with ACE inhibition activity. The functional group interaction energy descriptors used in the regression analysis were obtained by a series of inhibitor structures derived from molecular mechanics and semi-empirical calculations. The descriptors calculated using electrostatic and steric fields from the precisely defined functional group were sufficient to explain the biological activity of inhibitor. Application of the descriptors to the inhibition of ACE indicates that the derived QSAR has good predicting ability and provides insight into the mechanism of enzyme inhibition. The method, functional group interaction energy analysis, is expected to be applicable to predict enzyme inhibitory activity of the rationally designed inhibitors.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.630-634
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• 2007

In the past, the use of wave energy has mainly been focused on conversion of large wave energy resources in the far offshore areas. However, with the technological improvement of converting wave energy into electricity, the energy resources at much shallow waters are now considered as a site for possible installation of the devices that obtain energy from the waves. In this respect, the wave energy resources on the east coast of Korea, where the sea is milder than the open ocean, were investigated using the field measurement data obtained at three different locations along the coast. For all the locations, the wave power was greater in winter season, compared to summer season. The estimated wave power varied from 2 to 4.5 kW/m on average, depending on the measurement locations.