• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.6
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• pp.60-67
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• 2008

A low-power 2.4GHz fractional-N frequency synthesizer has been designed for 2.4GHz ISM band applications such as Bluetooth, Zigbee, and WLAN. To achieve low-power characteristic, the design has been focused on the power optimization of power-hungry blocks such as VCO, prescaler, and ${\Sigma}-{\Delta}$ modulator. An NP-core type VCO is adopted to optimize both phase noise and power consumption. Dynamic D-F/Fs with no static DC current are employed in designing the low-power prescaler circuit. The ${\Sigma}-{\Delta}$ modulator is designed using a modulus mapping circuit for reducing hardware complexity and power consumption. The designed frequency synthesizer which was fabricated using a $0.18{\mu}m$ CMOS process consumes 7.9mA from a single 1.8V supply voltage. The experimental results show that a phase noise of -118dBc/Hz at 1MHz offset, the reference spur of -70dBc at 25MHz offset, and the channel switching time of $15{\mu}s$ over 25MHz transition have been achieved. The designed chip occupies an area of $1.16mm^2$ including pads where the core area is only $0.64mm^2$.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.447-454
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• 2013

A model-based method is proposed to diagnose the gear crack in the gearbox under variable loading condition with the objective to apply it to the wind turbine CMS(Condition Monitoring System). A simple test bed is installed to illustrate the approach, which consists of motors and a pair of spur gears. A crack is imbedded at the tooth root of a gear. Tachometer-based order analysis, being independent on the shaft speed, is employed as a signal processing technique to identify the crack through the impulsive change and the kurtosis. Lumped parameter dynamic model is used to simulate the operation of the test bed. In the model, the parameter related with the crack is inversely estimated by minimizing the difference between the simulated and measured features. In order to illustrate the validation of the method, a simulated signal with a specified parameter is virtually generated from the model, assuming it as the measured signal. Then the parameter is inversely estimated based on the proposed method. The result agrees with the previously specified parameter value, which verifies that the algorithm works successfully. Application to the real crack in the test bed will be addressed in the next study.

• Journal of the Korean Arthroscopy Society
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• v.9 no.1
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• pp.60-64
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• 2005

Purpose: To describe the impingement of the osteophyte between the olecranon process and olecranon fossa and to understand the effect of removing the lesion on the elbow extension in heavy workers. Materials and Methods: Arthroscopy was performed to elbow of heavy industrial workers who complained painful limitation of elbow extension.6 patients(Teases) with average age of 43 year were selected. The average ROM showed flexion contracture of $17^{\circ}$ and further flexion of $87^{\circ}$. Results: In all cases, after the operation two months follow up, mean flexion contracture improved from $17^{\circ}\;to\;2^{\circ}$ with further flexion from$87^{\circ}\;to\;122^{\circ}$. After the operation 1 year follow up, the mean flexion contracture was $3^{\circ}$ and further flexion was $113^{\circ}$. Pain relief within acquired range of motion was achieved in all cases and there was no complication in this series. Conclusion: Selective removal of the impingement bony spur for treatment of flexion contracture in the patient with chronic cumulative trauma disorder patients appear to be effective method to control pain, recover joint movement and at] ow early rehabilitation.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.97-101
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• 2002

Purpose : To describe clinical results and improvement of range of motion and pain after arthroscopic treatment for the athletic elbow lesion. Materials and Methods : We reviewed 13 cases of functional restriction of the elbow motion, who all patients were treated by conservative treatment during than 6 months but failed. We performed arthroscopic osteophytectomy, capsular release, spur excision. The interval from injury to operation was average of 13 months (range, eight to sixteen months). We used the Broberg and Morrey functional rating score system in evaluating result. The follow-up period averaged 6 months. Results : Arthroscopic finding that moderative to severe synovitis in all cases, intraarticular loose body in 9 cases, olecranon bony spur in 2 cases, was observed. All cases were successfully improved in range of motion and pain without in any further operation. Preoperative average score was 65 and postoperative average score was 89.4 in Broberg and Morrey functional rating score. Conclusions : Arthroscopic treatment appear to be satisfactory management modality due to diagnose the casative factor and reduce the injury around the elbow joint in painful elbow lesion. Elbow arthroscopy appears to be a safe and effective treatment for athletes, allowing easy return to participation in sports.

• Korean Journal of Food Science and Technology
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• v.9 no.1
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• pp.13-18
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• 1977

In order to improve the storage ability of Spur Red Delicious apple, calcium ingredients were applied to the apple tree during the growing period, and then the effects of calcium on appearances and respiratory activity of harvest apples were investigated during the storage period. The results of this work were summarized as follows: 1. The freshness of apples treated by calcium compounds reached $73{\sim}78%$, but that of control group was 68% by March of next year. 2. The respiratory rate of the apples that had been applied the high concentration of ammonium sulfate in field during the growing period, was accelerated rather than control group, and that of calcium treatment groups was continuously inhibited during the storage period. 3. The direct foliar application of calcium compounds in the field was more effective than dipping apples in calcium chloride solution for better quality and improving storage ability after harvest. 4. The freshness and hardness relatively not much decreased in calcium treatment groups even after 5 month storage.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.801-810
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• 2019

This study analyzes the impact on geomorphic changes downstream due to alternate bars developed weir upstream through laboratory experiments. The disturbance, such as a spur in the side wall, of the flow at the inlet of the channel triggers the development of alternate bar upstream at the beginning of the experiment, and gradually moved downstream with keeping their shapes over time. The bed in the downstream of weir in the mid of channel scoured due to the scarcity of sediment inflow because weir upstream traps it. Moreover, bar migration speed decreases as the bars approaches to the weir with time. However, as time increases, the alternate bars upstream migrate over the weir, and sediment in the eroded bed of the weir downstream are deposited. The phase of the bar upstream changes oppositely after passing through the weir. The phase of the bar downstream changes rapidly as the shape of alternate bar is clear upstream, which is affected by the strong disturbance. The phase of bar changes, and the bar migration speed decreases gradually with time, and finally stopped due to forcing effects on the bar by the disturbance. The faster the reaction of alternate bar with a long spur, the larger the bar height formed downstream and the shorter the bar length. This means that the larger the forcing effect of bar, the more it affects the bar migration. In addition, although the size of the alternate bar increases over time, the bar doesn't migrate downstream and a forced bar is generated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2380-2386
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• 2013

A PLL with an unipolar charge pump and a loop filter consisting of sample-hold capacitor and 2nd-order RC filter has been proposed. The goal of the proposed PLL is the suppression of reference spur which is caused by charge pump mismatch. It also improves phase noise characteristic. It has been designed with a 1.8V $0.18{\mu}m$ CMOS process and proved by HSPICE simulation.

• Journal of The Korean Astronomical Society
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• v.44 no.5
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• pp.177-193
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• 2011

We present a photometric study of five open clusters (Czernik 5, Alessi 53, Berkeley 49, Berkeley 84, and Pfleiderer 3) in the Sloan Digital Sky Survey. The position and size of these clusters are determined using the radial number density profiles of the stars, and the member stars of the clusters are selected using the proper motion data in the literature. We estimate the reddening, distance and age of the clusters based on the isochrone fitting in the color-magnitude diagram. The foreground reddenings for these clusters are estimated to be E(B - V ) = 0.71 - 1.55 mag. The distances to these clusters are derived to be 2.0 - 4.4 kpc, and their distances from the Galactic center range from 7.57 kpc to 12.35 kpc. Their ages are in the range from 250 Myr to 1 Gyr. Berkeley 49 and Berkeley 84 are located in the Orion spur, Czernik 5 is in the Perseus arm, and Pfleiderer 3 and Alessi 53 are located beyond the Perseus arm.

• Architectural research
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• v.12 no.2
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• pp.63-72
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• 2010

Affordable housing has been a critical issue in the face of global economy and notably formulated a crucial agenda of the housing policy. While each local government seriously considers many approaches to providing affordable housing, a unique and innovative way to address it at a community level is fully uncovered, particularly nonmetropolitan areas where resources for economic development are limited and vulnerable. The purpose of this study is to examine the mechanism of the provision of affordable housing for the elderly in nonmetropolitan areas. In doing so, this research investigates the housing development and delineates it as one viable solution that stimulates local communities. The affordable housing development, as a viable option to spur local development and vibrate community, is closely reviewed, and the factors to make it feasible are drawn. The findings indicate that it is widely recognized that keeping the elderly in the community positively contributes to maintaining a sustainable community. In fact, the idea of affordable housing development for middle-class elderly people is brought by one inspired long-time resident, and it is expedited by the consensus and cohesion of local community. The development stimulates local businesses in relation to housing, and all homes sold by the elderly moving in the new housing are available for young families. Also, the presence of affordable housing for the elderly who are able to independently live is extended to a picture of aging-in-place at a broader level.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.72-76
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• 2010

Osteochondroma is the one of the most benign tumors of the axial skeleton, but is rarely found in the facial bones. Typical facial features of condylar osteochondroma include striking facial asymmetry, malocclusion with openbite on the affected side, and prognathic deviation of the chin and crossbite to the contralateral side. In this case, twenty four year-old female showed facial asymmetry, chin deviation, openbite on the affected side but have no symptoms of pain or dysfunction. Concomitantly she had maxillary occlusal cant and hemimandibular hypertrophy. Panoramic radiograph showed radiopaque mass on right mandibular condyle extended along the lateral pterygoid muscle. Computed tomogram demonstrated enlarged condylar head and bony spur on posteromedial side of condyle and 99Tc bone scintigraphy showed a focal hot image. These findings were correspond with osteochondroma. The lesion was treated with condylectomy and residual facial asymmetry was corrected with 2-jaw orthognathic surgery. Herein, we report a case of osteochondroma of the mandibular condyle and accompanying facial asymmetry.