• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.3
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• pp.237-242
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• 2014

Surge phenomenon can be occurred in a compressor when the performance of turbofan engine for an aircraft is changed considerably such as take-off phase. This study is aimed to avoid surge phenomenon. This paper propose the PID and Fuzzy control System for the turbofan engine with control inputs, the VIGV(Variable Inlet Guide Vane) in closed loop, and the fuel mass flow in open loop. We design the Dynamic modeling, NPSS S-function, which is connection block of simulink between NPSS(Engine analysis program) and Simulink. Finally, we certify the performance to prevent a serge phenomenon in the VIGV control system using the both methods, PID and fuzzy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1499-1513
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• 2014

This paper proposes a novel blind image watermarking scheme exploiting Block Truncation Coding (BTC). Most of existing BTC-based watermarking or data hiding methods embed information in BTC compressed images by modifying the BTC encoding stage or BTC-compressed data, resulting in watermarked images with bad quality. Other than existing BTC-based watermarking schemes, our scheme does not really perform the BTC compression on images during the embedding process but uses the parity of BTC quantization data to guide the watermark embedding and extraction processes. In our scheme, we use a binary image as the original watermark. During the embedding process, the original cover image is first partitioned into non-overlapping $4{\times}4$ blocks. Then, BTC is performed on each block to obtain its BTC quantized high mean and low mean. According to the parity of high mean and the parity of low mean, two watermark bits are embedded in each block by modifying the pixel values in the block to make sure that the parity of high mean and the parity of low mean in the modified block are equal to the two watermark bits. During the extraction process, BTC is first performed on each block to obtain its high mean and low mean. By checking the parity of high mean and the parity of low mean, we can extract the two watermark bits in each block. The experimental results show that the proposed watermarking method is fragile to most image processing operations and various kinds of attacks while preserving the invisibility very well, thus the proposed scheme can be used for image authentication.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.1
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• pp.67-74
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• 2015

Computer-guided surgery utilizing computed tomography is advantageous in placing implants precisely and conveniently. The purpose of the cases was to report a newly developed CT-based guide fabrication program and subtractive manufacturing using resin block. The guided surgery with the program and subtractive manufacturing allows not only precise translation of the treatment plan, but also offers additional significant benefits.

• Journal of Korean Foot and Ankle Society
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• v.27 no.3
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• pp.112-116
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• 2023

A 74-year-old female patient, who underwent surgery for a left distal tibiofibular fracture 40 years earlier, visited the hospital with an ankle varus deformity due to malunion. The patient complained of discomfort while walking due to the ankle and hindfoot varus deformity but did not complain of ankle pain. Therefore, correction using supramalleolar osteotomy was planned, and through virtual surgical simulation, it was predicted that a correction angle of 24° and an osteotomy gap open of 12 mm would be necessary. An osteotomy guide and an osteotomy gap block were made using three-dimensional (3D) printing to perform the osteotomy and correct the deformity according to the predicted goal. One year after surgery, it was observed that the ankle varus was corrected according to the surgical simulation, and the patient was able to walk comfortably. Thus, for correction of deformity, virtual surgical simulation and a 3D-printed osteotomy guide can be used to predict the target value for correction. This is useful for increasing the accuracy of correction of the deformity.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.307-310
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• 1998

Selective lumbosacral radiculography and nerve root block techniques are very useful in determining the nerve root involved. We have done the lumbar root block to 61-year-old female who had suffered from low back pain radiating to right lower leg which was not relieved by epidural steroid injection two times. $L_5$ root block was performed under the fluoroscopic C-arm guide. When the needle was in correct position, we injected contrast medium (Isovist$^{(R)}$ - 300, Schering, Germany). After we injected 1.5 cc isovist, the S1 root was figured but L5 root was not figured. When we reinjected 1.5 cc isovist, $S_1$ root was enhanced and $L_5$ root was slightly visible due to severe disc bulging and lateral spinal stenosis.

• Journal of Biosystems Engineering
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• v.11 no.2
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• pp.14-22
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• 1986

This study was carried out to find a method which can be used to measure the soil moisture content of the soil bin exactly and quickly. And gypsum block is used as an instrument in measuring soil moisture content in the field of green house farming, etc.. However the characteristics of gypsum block, or the guide line of making gypsum block is not well introduced in Korea. So the information about gypsum block such as the density of gypsum, type of electrode, dimension of electrode, distance between electrodes, density of surrounding soil were included in this study and their effects on the relationship between soil moisture content and electrical resistance were investigated. The results of this study are as follows; 1. The grid type electrode was quicker in accessing the equilibrium condition and showed more sensitive response to the change of soil moisture content than the plate type electrode. 2. The longer the distance between the electrodes, the larger the electrical resistance, and the distance of 3 to 5 mm was recommended. 3. The larger the width of the electrode, the smaller the electrical resistance. However, there was no significance between the levels designed in this study. Considering the size of the gypsum block itself, the adaptible range of width may be 4 to 8 mm. 4. The higher the density of gypsum, the smaller the electrical resistance. And the block of lower density was broken down in the soil of higy moisture content. The optimum ratio of gypsum to water was 7:5. 5. The measuring system used in this study allowed simultaneous, multi-data acquisition. So this system using A/D converter can be applied to the measurement of soil moisture content of soil bin.

• Archives of design research
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• v.14 no.2
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• pp.279-292
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• 2001

The network drafting is introduced by american weaver Alice schlein, that is not a new weave, but a way of exploring old structures and driving them a new design. It was evident that larger scale pattern design produced on computer dobby-that is a loom without a jacquard mechanism, draw harness, or other extra patterning devices. Therefore, this study explored that developing and new weave design through the processing of network drafting In give a guide based on it In this process, the results of this study were as follow. A network is a collection of legal threading position that is constructed from a building block, called an "initial" which is the smallest identifiable unit of the threading. The process of network drafting produces large-scale designs without the chunky look of block weaves in addition In infinite potential variation on a singles threading through changes in tie-ups and dobby peg plan. It can get various new drafting through using of isolated, connected, disconnected pattern line.

• Korean Institute of Interior Design Journal
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• no.40
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• pp.94-101
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• 2003

This study is mentioning about basic information and guide related block types, through a comparison and an analysis of floor types which is shown as function in block types and public interior spaces. For the range of this survey, it is defind in the beginning of 1970' s to the end of 1990' s which was rapidly developed in hotel industry and also is chosen by 12 places in the first class hotels. On the purpose of this study is written by designing the basic information of architectures, new hotels which are built and managed in urban, refer to the survey and analysis of the characteristic in hotel. The following is conclusion by based on pre-survey of the analysis of a plan and a site in these hotels. First, as a result of analysis in block type, there are equally distributed in three types (in-type, combination type, close-type), except a atrium type exception, in 12 hotels(100%). Second, as a result of analysis of function type in public interior space, Con-course type is consist of 7(58%), Hall type is 5(42%) in the type of room in public interior space, in 12 hotels(100%). Third, the type in lobby on space plan are equally shown by the type of lobby in center(4PL.), of lounge in center(4PL.), and a compromising type(4PL.).

• The Korean Journal of Pain
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• v.10 no.1
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• pp.77-81
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• 1997

Background : We studied the effects of lumbar spinal root block (RB) prospectively in 21 patients who had suffered from low back pain with radiating pain even treated epidural steroid injection three times. Method : RB was performed under the fluoroscopic C-arm guide. When the needle was in correct position, we confirmed the needle placement and expected drug spreading by injection of contrast medium ($Isovist^{(R)}$-300, Sobering, Germany). Next 2% mepivacaine 1 ml mixed to 40 mg of Depomedrol was injected. Pain assessment was carried out 7 days after RB by numeric pain score regarding the pain just before RB was 10. Remained pain after RB was graded as excellent; 0-2, good; 3-5, bad; 6-8 and poor 9-10. Results : Mean age of the patients was 52.3 years. 38.1% and 47.6% of the patients showed excellent and goo dresults after RB, respectively. Conclusion : We concluded that RB is easy and safe procedure to perfirm and effective for the treatment of remnant pain following epidural steroid injection, especially in the patients who had spinal stenosis.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.202-208
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• 2016

The scope of activities of the visually impaired is increasing. But they are not easy to visit the destination safely because the building was complicated and larger than ever. There is a guide system for visually impaired such as GPS and Audio alerts, Braille guide block, Acoustic signaller, etc. But they are not suitable for indoor because most of them are the outdoor guide system. Therefore, in this paper, I propose a system that provides guidance information to the visually impaired using Voice Technology, TTS (Text to Speech) and Haptic Technology, Beacon based on the wireless sensor networks. It informed the visually impaired of guidance information about destination such as distance, height, and obstacle to the destination using the generalized smart phone. The user could be received guide info about searches for the optimal route to the destination using the TTS technology and Haptic technology in test result of the proposed system.