• Journal of the Korean Wood Science and Technology
• /
• v.40 no.6
• /
• pp.418-423
• /
• 2012

In order to develop the end use of cylindrical laminated veneer lumber (LVL) such as wooden crafts, the water proof-bonding strength, the resistance to abrasion and the surface hardness by painting the surface of LVL were investigated. The study results were as follows; The water proof-bonding strength through 5 cyclic test by boiling in water immersion and drying were favorable without delamination of glue line. Then the formulation of glue was resorcinol resin (100) to hardener of paraformaldehyde (5) by mixed weight percentage. The resistance to abrasion was relatively higher at cross section than tangential section. When tangential section of LVL was painted by UV protection oil, the resistance to abrasion was improved. In case of an cross section of LVL, the higher surface hardness appeared at larch core than radiata pine LVL. Also, in case of an tangential section of LVL, the higher surface hardness appeared at glue line than veneer side.

• Korean journal of communication and information
• /
• v.49
• /
• pp.39-56
• /
• 2010

This study on the exposed the viewers diversity as a basic cable television service. Diversity is the most basic goal of broadcasting policy has important implications. But still, such as cable and pay-media research on the viewing diversity has made a limited basis. SO much to offer for the cable offers viewers receive the number of channels available to compare the diversity of the field was verified. Price rises of analysis for the cable the more the number of channels offered to supply the channel has increased the diversity of the field. SO granted in accordance with the results of a market strategy, but for a variety of channels to be provided by a policy perspective, the price depending on the choice of a variety of audiences can be quite limited means. That is a wide range of viewers watching the channel had a right to be limited. These phenomena to improve the pay television service and the need to manage the Product channel diversity index was raised.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.3
• /
• pp.1711-1717
• /
• 2014

There have been many studies on IEEE 802.15.4 for home area networks(HAN) in Smart Grids. Existing unslotted or slotted IEEE 802.15.4 has almost not met strict conditions of the U.S. Department Of Energy(DOE). This study proposed a improved algorithm that reduces collisions, delay time and changes in the delay time. For this purpose, numbers were given to nodes to make the transmission in the order of the node numbers. Since the probability of the occurrence of collisions would decrease compared to random transmission if the nodes were given numbers, Backoff time was set at 0. In the proposed Numbered-Unslotted-ZeroBackoff algorithm, when the packet size was 133 octets and less than 180 packets per second occurred, it was found that packet delivery ratio was over 99.99%, and that all the maximum delay, the mean delay and the minimum delay were less than 0.02 seconds. This paper could confirm that the algorithm proposed in this study met the strict conditions of the DOE.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.5A
• /
• pp.496-503
• /
• 2010

The implementation of a RF transceiver for WRAN(Wireless Regional Area Network) system based on IEEE 802.22 standard using Cognitive Radio technology is presented in this paper. A CMOS RF transceiver IC for WRAN system operates in VHF/UHF(54~862MHz) broadband, and employs dual-path direct-conversion configuration and the in-band harmonic distortions are effectively suppressed by exploiting the dual-path direct conversion architecture. For 64QAM(3/4 coding rate) OFDM signal, an EVM of <-31.4dB(2.7%) has been achieved at 10dBm off-chip PA output power and the total chip area with pads is 12.95 mm2. The experimental results show that the proposed CMOS RF transceiver IC has perfect performance for WRAN system based on TDD(Time Division Duplex) mode.

• Clinical and Experimental Pediatrics
• /
• v.50 no.7
• /
• pp.694-697
• /
• 2007

Paroxysmal kinesigenic dyskinesia (PKD), previously referred to as movement-provoked seizures, is a rare neurological condition that is characterized by short duration dystonic or choreoathetotic movements precipitated by sudden movement, a change in position or hyperventilation. It can be difficult to distinguish this syndrome from seizures. We reported on three brothers in one family all of whom developed abnormal involuntary dystonic or choreoathetotic movement with a tingling or stiffness sensory aura. Evaluations of the patients included general physical examinations, endoclinologic, metabolic studies, chromosomal analysis, video electroencephalograms and brain MRI imaging. All of these studies were normal except for an arachnoid cyst found in one patient. All symptoms showed excellent response to oxcarbamazepine ($Trileptal^{(R)}$) or carbamazepine. Use of the video electroencephalogram can help differentiate familial PKD from seizures.

• International Journal of Highway Engineering
• /
• v.10 no.4
• /
• pp.19-29
• /
• 2008

To produce asphalt mixtures at temperature significantly below $135^{\circ}C$, called "Warm Mix Asphalt (WMA)", new technologies are currently being developed worldwide. To produce WMA mixtures in this research, foaming technology is adopted to effectively disperse asphalt binder at lower temperature than hot mix asphalt (HMA) in the field. The main objectives of this study are to develop WMA process using foaming technology (WMA-foam) and evaluate its performance characteristics under various temperatures and loading conditions. WMA-foam mixtures were produced by injecting PO 64-22 foamed asphalt into warm aggregates whereas WMA mixtures were produced by adding PO 64-22 asphalt (without foaming) in the warm aggregates. Both dynamic modulus and flow number of WMA-foam mixtures were higher than those of WMA mixtures. Based on the limited dynamic modulus and repeated load test results, it is concluded that the WMA-foam mixtures using warm aggregates at $100^{\circ}C$ are more resistant to fatigue cracking and rutting than WMA mixtures.

• Korean Journal of Medicinal Crop Science
• /
• v.10 no.2
• /
• pp.88-92
• /
• 2002

The production of anthraquinone has been dectected in transformed roots of Rheum undulatum L. The effects of medium, initial pH, concentration of sucrose, light irradiation and elicitors on anthraquinone production in transformed roots of Rheum undulatum L. were investigated. The maximum production of anthaquinone was achieved in WPM medium (pH 5.7) supplemented with 6% sucrose, 0.5 mg/l $GA_3$, and 50 mg/l chitosan at 16h light $(16{\mu}mol\;m^{-2}s^{-1})$ condition. Under the optimum conditions, the production of anthraquinone reached to 0.18 mg/g(F.W.) after 8 weeks. The content was estimated about 1.3 times of the level of native roots.

• Journal of Engineering Education Research
• /
• v.8 no.1
• /
• pp.20-30
• /
• 2005

Recently, a new education paradigm 'Self-directed Learning' has attracted considerable attention. Problem-Based Learning (PBL) has been recognized as methodology to help students expand scientific thinking and knowledge. improve applicability, develope critical knowledge, and creatively solve problems. There have been significant efforts to develope PBL-based courses in mechanical engineering. A new PBL-based, multi-disciplinary course 'Product Dissection and Design Reasoning' has been developed in this paper. The course examines the way in which products and machines work and is intended to show freshman or sophomore level students how fundamental physical principles relate to engineering practice through hands-on dissection experience : thus, the course emphasizes the importance of knowledge of the fundamental physics for design reasoning. The primary role of this course is to develop creative design manpower. This paper describes the philosophy and content of this course and presents results from one year of development.

• Journal of Biomedical Engineering Research
• /
• v.23 no.4
• /
• pp.309-315
• /
• 2002

Since the discovery, in the 1980s, of erosion-pit-induced fractures in implanted mechanical heart valves. cavitation on the surface of mechanical heart valves has been widely studied as a possible cause of pitting. Several factors, including peak dp/dt of the ventricular pressure. maximum closing velocity of the leaflet, and squeeze flow. have been studied as indices of the cavitation threshold. In the present study. cavitation erosion on the surface of a mechanical valve was examined by focusing on squeeze flow and the water hammer phenomenon during the closing period of the valve. In this study, we measures pressure wave forms near a valve and closing velocities of a disk, which were placed in a holder with and without compliance. In case of all holders, pressure drop of below vapor pressure expect at near the surface disk. It was also found that the closing velocity of the disk increased and that cavitation erosion was enhanced too. These results suggest that disk closing velocity during the closing phase has signifiant effects on pitting erosion.

• Tuberculosis and Respiratory Diseases
• /
• v.55 no.6
• /
• pp.631-635
• /
• 2003

Idiopathic interstitial pneumonia is a group of lung disease classified by clinical, radiological and pathologic findings. Steroid is described in many reports as an effective treatment for the idiopathic interstitial pneumonitis. For the treatment of steroid non-responders, immuno-suppressive or cytotoxic agents are used as second line drug of choice. We experienced a case of nonspecific interstitial pneumonitis who was treated initially with glucocorticoid and antibiotics without effects, but later did respond to cyclosporin treatment. This 63 year-old patient was admitted due to dyspnea, cough, and sputum production. He was started on glucocorticoid and antibiotics after he was diagnosed as having nonspecific interstitial pneumonitis by open lung biopsy. The initial steroid treatment was not effective, however, after cyclosprin treatment, the patient showed clinical and radiologic improvements.