• Proceedings of the KSRS Conference
• /
• 2005.10a
• /
• pp.245-245
• /
• 2005

This paper addresses the use of directional textural information for connecting road segments. In urban scene, some roads are occluded by buildings, casting shadow of buildings, trees, and cars on streets. Automatic extraction of road network from remotely sensed high resolution imagery is generally hindered by them. The results of automatic road network extraction will be incomplete. To overcome this problem, several perceptual grouping algorithms are often used based on similarity, proximity, continuation, and symmetry. Roads have directions and are connected to adjacent roads with certain angles. The directional information is used to guide road fragments connection based on roads directional inertia or characteristics of road junctions. In the primitive stage, roads are extracted with textural and direction information automatically with certain length of linearity. The primitive road fragments are connected based on the directional information to improve the road network. Experimental results show some contribution of this approach for completing road network, specifically in urban area.

• Agricultural and Biosystems Engineering
• /
• v.1 no.1
• /
• pp.38-42
• /
• 2000

Though the freshness for agricultural products is an important factor related to their quality management, this terminology is being used restrictedly because it is very subjective. In this study, a dimensionless index which had the span of the maximum of 1 through the minimum of 0 was proposed to describe freshness of the product with time-variant quality and was applied to Tsugaru and Fuji apples. First, the compressive properties having the linearity in their change regarding time elapsed after harvest were selected. For Tsugaru apple, bio-yield and rupture forces had high correlation with time while for Fuji, bio-yield and rupture deformations had high correlations. When the slope, or ratio of force to deformation, was considered, the effect of cultivar could be neglected. When the linearly time-variant compressive properties for Tsugaru and Fuji apples were involved in the freshness indices, they described well freshness of apples. Also, the freshness decay constant depicted a characteristic which related to freshness decay rate. Therefore, the freshness index can be utilized to manage the quality during storage and distribution of apples.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.11
• /
• pp.2006-2010
• /
• 2008

In this paper, we fabricated a biosensor for detecting hydrogen peroxide and investigated the sensing property. We prepared a viologen and hemoglobin modified gold electrode using self-assembly and layer by layer method. The electrochemical property of the viologen derivative was characterized in 0.1 M $NaClO_4$ electrolyte solution by cyclic voltammetry. The modified electrode showed reversible electrochemical properties and high stability. From the results, the viologen can act as a charge transfer mediator for access to the electrode surface. The catalytic characteristics of the designed sensor proved that hemoglobin has been kept in its natural structure and can retain its biological activity. The designed biosensor showed a fast amperometric response, excellent linearity and low detection limit. In addition, it had high sensitivity, good reproducibility and stability.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.26-29
• /
• 2000

The conventional types of X-ray generators were bulky in physical size and heavy in weight and the control accuracies of the output voltages were not always satisfacotry. The high frequency switching inverter and converter technology on power conversion and control systems have been greatly closed up introducing power semiconducot devices. To decreasing the volume and the weight of high voltage transformer and to stabilize ripple. In this paper the newly developed x-ray generator in a low cost using duty modulation PWM inverter. This system verify improved performance by stabilize ripple of X-ray tube voltage and compared the reproducibility linearity and dose in single phase three phase and PSU.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.7
• /
• pp.356-363
• /
• 2001

A SRG (Switched Reluctance Generator) has many advantages such as high efficiency, low cost, high-speed capability and robustness compared with other of machine. But the control methods that have been adopted for SRGs are complicated. This paper proposes a simple control method using the PID controller which only controls turn-off angles while keeping turn-on angles of SRG constant. In order to keep the output voltage constant, the turn-off angle for load variations is controlled by using linearity between the generated current and turn-off angle since the reference generated current can be led through the voltage errors between the reference and the actual voltage. The suggested control method enhances the robustness of this system and simplifies the hardware and software by using only the voltage and the speed sensors. The proposed method is verified by experiments.

• Journal of radiological science and technology
• /
• v.15 no.1
• /
• pp.107-113
• /
• 1992

Inverter type X-ray apparatus has been introduced and used several hospitals. Principle of inverter type X-ray generators are such as to convert the frequency of commercial power supply to high frequency and to control the high voltages for X-ray tube. Inverter generators are now on the way for futher development to elliminate single phase generators and three phase generators. We compared inverter type X-ray apparatus with conventional single phase 2 peak and three phase 12 peak, apparatus in the following aspects X-ray out put to tube voltage, linearity of X-ray out put to mA, HVL according to mA contrast to kV.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.12 s.189
• /
• pp.80-87
• /
• 2006

Seals are usually made from elastomer, a kind of rubber, and it has the non-linearity and hyper-elasticity. U-type seals are used to prevent the leakage of internal fluid sealed in hydraulic actuator because they have more excellent performance than O-rings or rectangular seals. As a core part of hydraulic actuator, U-type seal gives much effect on performance and reliability of actuator. This study considers an NBR U-type seal under high pressure of a hydraulic actuator, and provides its deformation, stress-strain characteristic and contact force using the non-linear finite element analysis. Analysis results are compared with the experimental ones performed by the self-developed testing equipment. Verification result shows that this study presents a good application process for the effective design of U-type seals under high operation pressure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.9
• /
• pp.1-10
• /
• 2006

In this paper, a new high resolution XGA-SLM is implemented through modification of a commercial TFT-LCD beam projector and its optical modulation characteristics as a spatial light modulator(SLM) is also analyzed. First, the optics module, projection lamp and fans are removed from a commercial beam projector and instead some electric circuits to compensate their removal are manufactured and then, by inserting them into the beam projector, a new XGA-SLM is finally implemented. Second, from some optical experimental results, this TFT-SLM is found to have a good optical linearity in amplitude and phase modulation characteristics as a function of the input gray levels. Especially, through implementation of a binary phase-type correlator such as BPEJTC by using the suggested TFT-LCD panel, the implemented SLM is proposed as a new relatively low-cost and high resolution SLM for optical information processing.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.3
• /
• pp.313-321
• /
• 2014

A low-power low-cost polar transmitter for EDGE is designed in $0.18{\mu}m$ CMOS. A differential delta-sigma modulator (DSM) tunes a three-terminal voltage-controlled oscillator (VCO) to perform RF phase modulation, where the VCO tuning curve is digitally pre-compensated for high linearity and the carrier frequency is calibrated by a dual-mode low-power frequency-locked loop (FLL). A digital intermediate-frequency (IF) pulse-width5 modulator (PWM) drives a complementary power-switch followed by an LC filter to achieve envelope modulation with high efficiency. The proposed transmitter with 9mW power dissipation relaxes the time alignment between the phase and envelope modulations, and achieves an error vector magnitude (EVM) of 4% and phase noise of -123dBc/Hz at 400kHz offset frequency.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.553-554
• /
• 2008

In a general way, Current scaling DACs are used in wireless communication systems. But there are degradations of important factors because of mismatch of current source corresponding to high resolution. To solve the problem, Calibration methods are researched lately. Mismatch of current source is corrected by Calibration method and then corrected current values are delivered to Core DAC. As a results, Degradations of important factors that produced by increment of non-linearity are suppressed by calibration method.