• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2662-2670
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• 2009

The effect of the reflector type for the SAW filter on the characteristics of the slanted finger IDT filter have been studied by computer simulation. The IDT was evaporated by Aluminum-Copper alloy. The design condition was optimized by the phase shift of the SAWfilter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness are $5,000{\AA}$, and the width and the space of reflector are $3.6{\mu}m$ and $2.0{\mu}m$, respectively. Frequency response of the fabricated SFIT filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 8.2MHz. And we could obtain that the return loss is less then 16dB, the ripple characteristics is probably 4dB and the triple transit echo is less then 18dB after when we have matched impedance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1718-1725
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• 2008

Until 1980s, Korean elementary school architecture has been stereotyped by standard drawings. But there have been very few researches focused on this subject, especially regional one. As an attempt to improve these conditions, this study reviewed standard drawings of elementary school architecture by Education Board of Seoul in 1964 and 1975. Both standard drawings were reviewed through items such as components making a set of standard drawings, floor plan, elevation design and subsidiary facilities. They have rectangular unit classrooms, single-corridor block plan and plain exterior having no symbolic images, which are the characteristics of typical Korean school architecture until 1980s. On the other hand, they reveal the unknown characteristics such as double-corridor block plan, classrooms in basement, toilets of conventional type placed on every floor and changes in details of openings and exterior wall.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.329-334
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• 2014

This paper proposes the hardware architecture of high performance multi-mode 2D forward transform for HEVC which has same number of cycles for processing any type of four TUs and yield high throughput. In order to make the original image which has high pixel and high resolution into highly compressed image effectively, the transform technique of HEVC supports 4 kinds of pixel units, TUs and it finds the optimal mode after performs each transform computation. As the proposed transform engine uses the common computation operator which is produced by analyzing the relationship among transform matrix coefficients, it can process every 4 kinds of TU mode matrix operation with 35cycles equally. The proposed transform block was designed by Verilog HDL and synthesized by using TSMC 0.18um CMOS processing technology. From the results of logic synthesis, the maximum operating frequency was 400MHz and total gate count was 214k gates which has the throughput of 10-Gpels/cycle with the $4k(3840{\times}2160)@30fps$ image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.130-136
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• 2008

This paper describes a low-power high-performance analog front-end block for $UHF(860{\sim}960MHz)$ band RFID tag chips. It satisfies ISO/IEC 18000-6 type C(EPCgolbal class1. generation2.) and includes a memory block for test. For reducing power consumption, it operates with a internally generated power supply of 1V. An ASK demodulator using a current-mode schmitt trigger is proposed and designed. The proposed demodulator has an error rate as low as 0.014%. It is designed using a 0.18um CMOS technology. The simulation results show that the designed circuit can operate properly with an input as low as $0.2V_{peak}$ and consumes $2.63{\mu}A$. The chip size is $0.12mm^2$

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.95-104
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• 2019

PURPOSE. To evaluate the effect of surface treatments and repair materials on the shear bond strength and to measure the fracture toughness of CAD/CAM provisional restoration materials. MATERIALS AND METHODS. Four CAD/CAM (3D printing: Nextdent C&B and ZMD-1000B Temporary, CAD/CAM resin block: Yamahachi PMMA disk and Huge PMMA block) and four conventional (monometacrylate: Jet and Alike, dimetacrylate: Luxatemp and Protemp 4) materials were selected to fabricate disk-shaped specimens and divided into six groups according to surface treatment (n=10). CAD/CAM materials were repaired with Jet or Luxatemp, while conventional materials were repaired with their own materials. The shear bond strength was measured by using universal testing machine. Ten rectangular column-shaped specimens for each material were fabricated to measure the fracture toughness by single edge v notched beam technique. Statistical analysis was performed by one-way ANOVA. RESULTS. The highest shear bond strength of CAD/CAM materials was achieved by SiC paper + sandblasting. It was also accomplished when repairing 3D printing materials with Luxatemp, and repairing CAD/CAM resin blocks with Jet. Yamahachi PMMA disk showed the highest fracture toughness. Nextdent C&B showed the lowest fracture toughness value but no statistically significant difference from Alike and Luxatemp (P>.05). CONCLUSION. In order to successfully repair the CAD/CAM provisional restoration, mechanical surface treatment and appropriate repair material according to the CAD/CAM material type should be selected. The CAD/CAM provisional materials have proper mechanical properties for clinical use as compared to conventional materials.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.233-238
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• 2021

Recently, blockchain technology accumulates and stores all transactions. Therefore, in order to verify the contents of all transactions, the data itself is compressed, but the scalability is limited. In addition, since a separate verification algorithm is used for each type of transaction, the verification burden increases as the size of the transaction increases. Existing blockchain cannot participate in the network because it does not become a block sink by using a server with a low specification. Due to this problem, as the time passes, the data size of the blockchain network becomes larger and it becomes impossible to participate in the network except for users with abundant resources. Therefore, in this paper, we are improved transaction as studied the zero knowledge proof algorithm for general operation verification. In this system, the design of zero-knowledge circuit generator capable of general operation verification and optimization of verifier and prover were also conducted.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.4
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• pp.331-338
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• 2004

Stress transfer to the surrounding tissues is one of the factors involved in the design of dental implants. Unfortunately, insufficient data are available for stress transfer within the regenerated bone surrounding dental implants. The purpose of this study was to investigate the concentration of stresses within the regenerated bone surrounding the implant using three-dimensional finite element stress analysis method. Stress magnitude and contours within the regenerated bone were calculated. The $3.75{\times}10-mm$ implant (3i, USA) was used for this study and was assumed to be 100% osseointegrated, and was placed in mandibular bone and restored with a cast gold crown. Using ANSYS software revision 6.0, a program was written to generate a model simulating a cylindrical block section of the mandible 20 mm in height and 10 mm in diameter. The present study used a fine grid model incorporating elements between 165,148 and 253,604 and nodal points between 31,616 and 48,877. This study was simulated loads of 200N at the central fossa (A), at the outside point of the central fossa with resin filling into screw hole (B), and at the buccal cusp (C), in a vertical and $30^{\circ}$ lateral loading, respectively. The results were as follows; 1. In case the regenerated bone (bone quality type IV) was surrounded by bone quality type I and II, stresses were increased from loading point A to C in vertical loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, concentrated on the top of the cylindrical collar loading point B and C in vertical loading. And, In case the regenerated bone (bone quality type IV) was surrounded by bone quality type III, stresses were increase from loading point A to C in vertical loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, B and C in vertical loading. 2. In case the regenerated bone (bone quality type IV) was surrounded by bone quality type I and II, stresses were decreased from loading point A to C in lateral loading. Stresses according to the depth of regenerated bone were concentrated on the top of the cylindrical collar in loading point A and B, distributed along the implant evenly in loading point C in lateral loading. And, In case the regenerated bone (bone quality type IV) was surrounded by bone quality type III, stresses were decreased from loading point A to C in lateral loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, B and C in lateral loading. In summary, these data indicate that both bone quality surrounding the regenerated bone adjacent to implant fixture and load direction applied on the prosthesis could influence concentration of stress within the regenerated bone surrounding the cylindrical type implant fixture.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.191-195
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• 2017

The microstructures of nonwoven fabric with and without nanofibers used as a filter for air purification type mask were investigated using scanning electron microscope. Moreover, we proposed a new mask design which is effective in the improvement of the fine dust blocking property. When comparing to nonwoven fabrics of which an average diameter was $25{\mu}m$, the nanofibers formed by the electrospinning process had a tight mesh structure arranged irregularly with a relatively large specific surface area, which could be associated with their much smaller diameter ranging from 25 to 120 nm. Such a prominent structural feature at nanofibers led to mechanical adsorption of fine particles, resulting in enhancement of filtering behavior maintaining high permeability. In addition to the excellent performance of the mask filter, wearing the mask properly is expected to maximize the blocking property of fine dust. To meet such a requirement, a new mask design that can be closely attached to the face in order to effectively block fine dust entering the gap between the face and the mask.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.744-754
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• 2016

Asphalt concrete track (ACT) is a track system connecting wide sleepers and concrete panels on top of an asphalt concrete layer; such a system requires adequate resistance force against various longitudinal and lateral external loads. In this study, a series of experiments were carried out to assess the longitudinal and lateral resistance force of a wide sleeper and concrete panel type ACT. The required shear resistance force of the horizontal displacement restraint device (HDRD) was evaluated. Furthermore, a concrete block type anchor and a steel pipe type anchor were developed as HDRDs. The shear resistance force was decided based on the experimental results of horizontal shear tests for each anchor system. In addition, proper numbers and arrangement design guidelines for the HDRDs were suggested considering the shear resisting capacity and economics for HDRDs applied to ACT.

• Physical Therapy Rehabilitation Science
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• v.8 no.2
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• pp.67-73
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• 2019

Objective: The purpose of this study was to compare the differences in the length of hospital stay between hemorrhage stroke survivors with health insurance and those with medical care after controlling all factors except for the type of medical insurance by using the propensity score matching (PSM) method. Design: Retrospective cohort study. Methods: Data from the Korean National Centers for Disease Control and Prevention's In-Depth Discharge Injury Survey between the years 2006 and 2012 were used for analysis. A total of 4,538 cases were defined as persons with hemorrhagic stroke (I60-I62) based on the block of categories in the International Classification of Diseases (10th). In order to analyze the inpatient period differences depending on the type of health care, which reflects one's socio-economic level, the chi-square and t-test was conducted. Results: Frequency and percentage were presented, and regression analysis was used to determine the factors affecting the inpatient period. Age, severity of disease, treatment outcome, and post-discharge status were no longer statistically significant after matching. The inpatient period of the persons receiving medical aid benefits was found to be significantly longer than those with national health insurance (p<0.05). Conclusions: The factors influencing the inpatient period of hemorrhagic stroke survivors were treatment outcomes, severity of disease, hospital admission process, and the type of health care. It is necessary for systematic and comprehensive governmental management for persons with hemorrhagic stroke to be transferred to long-term care facilities.