• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.34-42
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• 2010

The DOA(direction of arrival), which is based on parametric and nonparametric estimation algorithm, and adaptive beamforming algorithm for mobile communication environments are researched and analyzed. In parametric estimation algorithm, eigenvalues of the signal component and the noise component are obtained from correlation matrix of received signal by array antenna and power spectrum of the received signal is discriminated from them. Otherwise, in nonparametric estimation algorithm, we minimize a regularized objective function for finding a estimate of the signal energy as a function of angle, using nonquadratic norm which leads to supper resolution and noise suppression. And then, DOA is estimated by the signal and noise spatial steering vector, and adaptive beam-forming pattern is improved by weight vectors obtained from the spatial vector. Therefore, the improved directional estimation algorithm with regularizing sparsity constraints offers super-resolution and noise suppression compared to other algorithms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1270-1277
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• 2003

The extrusion conditions of the soymilk residue and corn grits mixtures were optimized. The experiment was designed according to the D-optimal design of response surface methodology (RSM), which shows 18 experimental points including 4 replicates for three independent variables (screw speed, water content and die temperature). The responses variables such as bending force, expansion ratio, bulk density, water solubility index (WSI), water absorption index (WAI), and color values (L＊, a＊, b＊) were evaluated using response surface analysis. Expansion ratio and WSI decreased with increasing water content, whereas bulk density tended to increase with increasing water content. While greater screw speeds enhanced WSI and yellowness, higher moisture contents decreased the expansion ratio and WSI value. However, die temperature did not influence upon the response variables. The optimum extrusion conditions by numerical and graphical methods were similar: the screw speed, water content, and die temperature were 250 rpm, 22.43% and l28.16$^{\circ}C$ by the numerical method; 250 rpm, 22.43%, and 128.02$^{\circ}C$ by graphical method.

• Composites Research
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• v.28 no.4
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• pp.226-231
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• 2015

Various characteristics(thermal expansion, microstructure, etc.) and mechanical properties of CNT-aluminum nano composites manufactured by volume production system were evaluated. Also, formability and durability were evaluated for potential applications in automotive parts, via compared with high-elasticity material (A390) and the current commercial product. As a result, this composite has excellent mechanical properties and formability, therefore, to verity its potential for application as light and high strength materials in automobile part.

• Tunnel and Underground Space
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• v.8 no.4
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• pp.332-341
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• 1998

Conventional polishing of stone panel edges has been done by hand. While this has changed somewhat with the advent of automatic machines, it is still very much a hand finishing technology. For the development of edge shape milling tool, the primary test on characteristics of edge shape milling tool was carried out. This paper presents the results of tests focused upon the milling capability that was varied by the variables of operation parameters. Author tried to confirm the effect of six operation parameters of equipment such as rotation speed, advance speed, applied load, water flow rate and rotational direction. The result from test was described in term of shape milling capability that was defined as cutting volume of rock by unit weight of tool wear. The variance of the results could indicate the optimum level of each operating parameters. The test was also carried out to determine the abrasion resistance varied according to the abrasive flow rate. The abrasion resistance was increased with the abrasive flow rate, but over some rate it was not changed.

• Restorative Dentistry and Endodontics
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• v.31 no.3
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• pp.179-185
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• 2006

This study was conducted to evaluate canal configuration after shaping by $ProTaper^{TM}$ with various rotational speed in J-shaped simulated resin canals. Forty simulated root canals were divided into 4 groups, and instrumented using by $ProTaper^{TM}$ at the rotational speed of 250, 300, 350 and 400 rpm. Pre-instrumented and post-instrumented images were taken by a scanner and those were superimposed. Outer canal width, inner canal width, total canal width, and amount of transportation from original axis were measured at 1, 2, 3, 4, 5, 6, 7 and 8 mm from apex. Instrumentation time, instrument deformation and fracture were recorded. Data were analyzed by means of one-way ANOVA followed by Scheffe's test. The results were as follows 1. Regardless of rotational speed, at the $1{\sim}2mm$ from the apex, axis of canal was transported to outer side of a curvature, and at 3~6 mm from the apex, to inner side of a curvature. Amounts of transportation from original axis were not sienifcantly different among experimental groups except at 5 and 6 mm from the apex. 2. Instrumentation time of 350 and 400 rpm was significantly less than that of 250 and 300 rpm (p<0.01). In conclusion the rotational speed of $ProTaper^{TM}$ files in the range of $250{\sim}400rpm$ does not affect the change of canal configuration, and high rotational speed reduces the instrumentation time. However appearance of separation and distortion of Ni-Ti rotary files can occur in high rotational speed.

• Journal of IKEEE
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• v.17 no.4
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• pp.407-417
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• 2013

In this paper, a reconfigurable peripheral unit for LED lighting communication is presented. Embedded lighting devices require various communication protocols. Usually, serial communication protocols and lighting control communication protocols such as DALI, DMX512, UART, SPI, IrDA, etc. are used in lighting devices. When the requirements of communication protocols are satisfied with separate IPs, the cost and the power consumption can considerably increase. We propose a reconfigurable communication peripheral unit which uses analysis of signal formats of the protocols. The gate count of the reconfigurable peripheral unit uses only 57% of the gate count of the separate implementation. Also, in this paper, a mapping table based DALI-ZigBee interfacing method for flexible lighting network configurations is proposed. Using this method, various DALI-ZigBee network systems can be easily set up. An LED lighting system platform is implemented to verify the operation of the DALI-ZigBee interfacing method. The reconfigurable peripheral unit and the DALI-ZigBee interfacing method can be efficiently used to implement various wired/wireless lighting communication systems.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.90-96
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• 2014

Purpose: The purpose of this study is to see what impact the heat and press-on-metal technique has on the marginal fit of metal ceramic crown. Materials and methods: Prior to the experiment, 4 metal master models were prepared. Each model has margin of chamfer, margin of heavy chamfer, margin of shoulder with bevel and margin of shoulder (collarless). Additionally, 10 crowns were made for each margin, total of 40 crowns. Marginal discrepancy between the master model and crown was observed at ${\times}100$ microscopic magnification in two states; in coping state and upon completion of making metal ceramic crown. Data analysis was performed using paired t-test along with one-way ANOVA and Duncan multiple comparison test. Results: After analyzing mean and standard deviation of marginal discrepancy, it was confirmed that marginal discrepancies were within the clinical permitted range for all states; in coping state and upon completion of making metal ceramic crown. For the chamfer group, a significant increase in marginal discrepancy upon completion of making metal ceramic crown was observed compared to the heavy chamfer group. Also, a marginal discrepancy of porcelain margin in shoulder group was significantly less than the marginal discrepancy of metal margin in chamfer and shoulder group. Conclusion: From the test result, one can conclude that marginal fit of metal ceramic crown built with heat and press-on-metal technique is not significantly different from marginal fit of metal ceramic crown built with traditional technique. And along with efficiency of this system, heat and press-on-metal technique is considered in clinic.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.126-136
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• 2009

Purpose: We evaluated the correlation of the anatomic parameters of the acromion those represent on the magnetic resonance image (MRI) of impingement syndrome. Materials and Methods: From June, 2004 to December, 2005, 71 cases were surgically proven to be impingement syndrome, and the anterior acromial hooking angle, the lateral acromial hooking angle (AAHA and LAHA) and the acromial hooking index (AHI: the sum of the AAHA and LAHA) were compared to 16 control cases. At the same period, 55 cases were surgically proven to be partial or full thickness rotator cuff tear, and age, gender and twelve anatomic parameters, including the acromial type, the acromial angle, the anterior covering, the acromial slope, the AAHA, the lateral acromial angle, the acromial torsional angle, the lateral acromial angulation, the LAHA, the lateral covering, the acromiohumeral distance and the AHI were assessed. Results: The AAHA and AHI were increased as impingement syndrome proceeded. The acromial type and acromial angle, and the AAHA, LAHA and AHI showed significant differences between the controls and the rotator cuff tear patients on univariant analysis. On multivariant analysis, gender was most strongly correlated with rotator cuff tear. Age, AAHA and the acromial angle showed similar correlation, respectively. Conclusion: The coronal acromial shape is correlated with rotator cuff tear, and it is important to correct the lateral acromial shape when performing acromioplasty.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.2
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• pp.92-97
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• 2011

Landfill is the main treatment method for bottom-ash because it has not only an irregular particle size and ingredients but also not proper recycling treatment. The aim of this study is to raise recycling rate of bottom-ash(nonplasticity pulverulent) and for the purpose of alternatives of clay to investigate the properties of Bottom-ash (B/A)-Hard Clay (H/C) bodies with controlled interfacial chemistry properties. After investigating the sedimentation height of suspensions with controlled pH, it was discovered that there was no hetero-polar aggregation for mixed slips because hard clay and bottom-ash had similar interfacial chemistry properties. Also, bulk density, water absorption, and microstructure properties of each pellet was observed that made by silp casting method and manufactured at $50^{\circ}C$ intervals between $1000{\sim}1250^{\circ}C$. As a result, dispersed slip of clay and bottom ash are possible for slip casting and plastic forming process because they exhibit Bingham plastic behavior. Products that made by slip with dispersed clay and bottom ash are not only suitable for KS L 4201 and KS L 1001 at $1250^{\circ}C$ but it is also possible to apply for ceramic and sanitary ware because specific gravity was about 15 % lighter than general ceramic materials.

• Restorative Dentistry and Endodontics
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• v.31 no.2
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• pp.125-132
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• 2006

This study was conducted to evaluate the insertion depth of Buchanan plugger after shaping by various Ni-Ti rotary files. It was conducted to determine which size of plugger are appropriate, when root canals are shaped with Ni-Ti rotary files and obturated by Continuous wave of condensation technique. Two type of eighty simulated resin blocks were used : J-shaped and straight shaped canal. The simulated canals were instrumented by ProTaper and ProFile. Buchanan pluggers were inserted into the canal, and then the image was recorded to scanner. The distance from the apex of the canal to the plugger tip was measured by image analysis program. Data were analyzed by one-way ANOVA followed by Scheffe's test. The results were as follows 1. In straight canal finished up to ProTaper F2 and F3 file, F and FM pluggers were inserted more than 5 mm short of working length. 2. In J-shaped canal finished up to ProTaper F2 file, F pluggers were inserted more than 5 mm short of working length. Finished up to ProTaper F3 file. F and FM pluggers were inserted more than 5 mm short of working length. 3. In straight and J-shaped canal finished up to ProFile .06/#20 and .06/#25, any of Buchanan plugger could not be inserted more than 5 mm short of working length. These results suggest that canals shaped by ProTaper could be obturated by Continuous wave of condensation technique with F and FM size Buchanan plugger.