• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.7
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• pp.549-555
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• 2015

A measurement technique of interfacial velocity in air-water separated flow by particle tracking velocimetry using an infrared camera (IR-PTV) was developed. As infrared light with wavelength in the range of 3-5 um could hardly penetrate water, IR-PTV can selectively visualize only the tracer particles existing in depths less than 20 um underneath the air-water interface. To validate the measurement accuracy of the IR-PTV technique, a measurement of the interfacial velocity of the air-water separated flow using Styrofoam particles floating in water was conducted. The interfacial velocity values obtained with the two different measurement techniques showed good agreement with errors less than 5%. It was found from the experimental results obtained using the developed technique that with increasing air velocity, the interfacial velocity proportionally increases, likely because of the increased interfacial stress.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.11-22
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• 2023

In this work, a depth-by-depth evaluation on the deterioration of concrete is suggested by utilizing disk shaped concrete specimens. Dynamic elastic modulus of cylindrical concrete was measured using a free-free resonance column method and compared with dynamic elastic modulus of disk-shaped concrete measured by impulse excitation technique(IET) and impact resonance(IR). According to the results of the experiment, both IET and IR methods showed a smaller difference in dynamic elastic modulus with smaller deviation in data when thickness of the disk specimen was increased. This trend was more evident from dynamic elastic modulus measured by IR method compared to that measured by IET. Variation in data was also smaller with the IR result. To increase the accuracy of the data, it is recommended to use the IR method for disk specimen with a diameter of 100mm and a thickness of 25mm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.1
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• pp.89-96
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• 2013

This paper presents an improved clutter signal removal algorithm using Singular Value Decomposition(SVD). For indoor positioning system using IR-UWB Radar, the target signal is extracted from received signal. We use clutter signal removal algorithm using SVD for target signal extraction. Clutter signal removal algorithm using SVD has the advantage of operation but the disadvantage of high computational complexity. In this paper, we propose a method to improve computational complexity. As the experimental results, it is confirmed that the method presented in this paper improve the computational complexity of clutter removal algorithm using SVD.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.426-433
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• 2006

In this paper, we propose an incremental redundancy(IR)-hybrid ARQ(HARQ) scheme which uses double binary turbo codes for error correction. We also propose a methodology for basic analysis of the throughput which is a performance index of HARQ. The proposed double binary turbo IR-HARQ scheme provides higher throughput than binary IR-HARQ, which uses binary turbo codes for error correction, at all $E_s/N_0$. An extra coding gain is also attained by using the proposed HARQ scheme over the coding gain achieved by turbo codes only.

• The KIPS Transactions:PartA
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• v.18A no.3
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• pp.109-114
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• 2011

We describe a technique for automatically proving compiler optimizations sound, meaning that their transformations are always semantics-preserving. As is well known, IR (Intermediate Representation) optimization is an important step in a compiler backend. But unfortunately, it is difficult to detect and debug the IR optimization errors for compiler developers. So, we introduce a C level error check system for detecting the correctness of these IR transformation techniques. In our system, we first create an IR-to-C converter to translate IR to C code before and after each compiler optimization phase, respectively, since our technique is based on the Memory Comparison-based Clone(MeCC) detector which is a tool of detecting semantic equivalency in C level. MeCC accepts only C codes as its input and it uses a path-sensitive semantic-based static analyzer to estimate the memory states at exit point of each procedure, and compares memory states to determine whether the procedures are equal or not. But MeCC cannot guarantee two semantic-equivalency codes always have 100% similarity or two codes with different semantics does not get the result of 100% similarity. To increase the reliability of the results, we describe a technique which comprises how to generate C codes in IR-to-C transformation phase and how to send the optimization information to MeCC to avoid the occurrence of these unexpected problems. Our methodology is illustrated by three familiar optimizations, dead code elimination, instruction scheduling and common sub-expression elimination and our experimental results show that the C level error check system is highly reliable.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.152-153
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• 2015

일반 영상의 영상확대를 위한 다양한 알고리즘이 존재한다. 하지만 IR 영상의 경우 일반영상과 다른 특성을 가지고 있기 때문에 IR 영상을 위한 영상 확대 알고리즘이 필요하다. 따라서 IR 영상이 일반영상에 비해 디테일이 없다는 특성을 고려하여 복잡한 알고리즘을 적용시키기 보다는 ADRC[1]와 같은 단순한 분류 기법을 활용하여 LR-HR 패치를 분류하고 학습된 데이터를 이용하여 영상확대 알고리즘에 적용하였다. 또한 알고리즘의 성능을 향상시키기 위해 학습과정에 전처리 과정을 추가하여 알고리즘 작동 시 연산량의 증가 없이 확대 영상의 선명도를 향상시키고자 하였다. 이와 같은 방법으로 영상 확대 알고리즘을 수행하였을 때 통상적인 영상확대 기법인 bi-cubic interpolation 기법보다 CPBD 수치가 평균 0.0527 만큼 높은 결과를 확인할 수 있었고 전처리 과정을 추가하였을 때 이전보다 평균 0.0119 만큼 더 선명해진 영상을 얻었다.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1065-1072
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• 2021

In Computed Tomography, abdominal examination showed the highest proportion of use, and effort of reducing the radiation dose is required. Recently introduced Iterative Reconstruction(IR) is repetitive reconstruction technique of Computed Tomography. SIEMENS' IR, ADMIRE and GE's IR, ASIR-V, were used in this examination. Noise, % Contrast, and High contrast resolution were measured by using ACR phantom for image quality evaluation. In addition, CTDI_vol and DLP displayed in the CT device were used for dose evaluation. When FBP and IR were compared, stage 2 to stage 5 of ADMIRE and 10, 30, 50, 70, and 90% of ASIR-V were applied, noise could be reduced from a minimum of 0.46 to a maximum of 2.38 in ADMIRE compared to FBP, and noise from a minimum of 0.51 to a maximum of 2.5 in ASIR-V compared to FBP. Also, % Contrast and High contrast resolution of FBP and IR were no statistical difference. When IR was used for abdominal CT examination, the radiation dose of ADMIRE is reduced by 25.39% compared to the radiation dose of FBP. Also, the radiation dose of ASIR-V is reduced by 16.61% compared to the radiation dose of FBP. In conclusion, it is believed that if IR is applied during abdominal CT examination, the radiation dose can be reduced without deteriorating the image quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.662-668
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• 2013

Mobile communication systems have been adopting link adaptive transmission schemes such as adaptive modulation and coding (AMC) and hybrid-ARQ (HARQ). Incremental redundancy (IR) HARQ scheme is known to be highly efficient in terms of throughput and power consumption and can be a good solution for mobile communication systems. In this paper, we propose an IR-HARQ scheme based on dual-diagonal parity-type block LDPC codes in which we define a transmission priority of coded bits and propose the sub-packet construction rule. We present the throughput performance of IR-HARQ with various modulation and coding and multi-antenna modes. Consequently, the proposed scheme provides the improvement of system throughput by elaborate link adaptation with CQI information.

• 한국지구물리탐사학회:학술대회논문집
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• 2009.10a
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• pp.185-189
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• 2009

Integrated analysis of GPR, impact echo and impulse response for detection of the rear cavity of concrete was performed on the test-bed which was made in the same scale and component ratio to the real concrete structure. GPR survey may roughly delineate the location of the cavity, but applying the IE and IR technique to the test-bed, the location was clearly identified.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.610-616
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• 2012

In this paper, we present a method to detect an object such as ship, rock and buoy from sea IR image for the safety navigation. To this end, we do the image smoothing first and the apply watershed algorithm to segment image into subregions. Since watershed algorithm almost always produces over-segmented regions, it requires posterior merging process to get meaningful segmented regions. We propose an efficient merger algorithm that requires only two times of direct access to the pixels regardless of the number of regions. Also by analyzing IR image obtained from sea environments, we could find out that most horizontal edge come out from object regions. For the given input IR image we extract horizontal edge and eliminate isolated edges produced from background and noises by adopting morphological operator. Among the segmented regions, the regions that have horizontal edges are extracted as final results. Experimental results show the adequacy of the proposed method.