• 대한의용생체공학회:의공학회지
• /
• 제36권5호
• /
• pp.150-154
• /
• 2015

Long time ultrasound scan can cause a temperature rise in human tissue and affect the physical body. This is closely connected with patients' safety. So many researchers have been studied on this matter with animals such as mammals and experimental rat, because diagnostic ultrasound has been used many types of human organ to find disease. Therefore, this study is tested on bean sprouts to search how far the tissue temperature changes because of the excessive scanning consequence from ultrasound diagnosis and frequent number of ultrasonic scanning and how much affect their growth. The United States and several European countries have restrictions for number of scanning, while South Korea does not have any limitation for using ultrasound diagnosis. Comparison was that how different condition affect its' growing. The testing group is like many pregnancy moms to have 50 minutes in B-mode and color doppler mode by linear, convex and sector probe every day for a week and the other is to scan only once during the testing period. As a result, it was confirmed that there was a significant growing difference on frequent ultrasonic scanning group compared to normal one. So the final conclusion is that there needs to have a significant limitation of ultrasound scan time and a number of inspection when having for diagnostic ultrasound and recommendation like USA and a few European countries.

• 한국컴퓨터정보학회논문지
• /
• 제26권6호
• /
• pp.9-17
• /
• 2021

본 논문에서는 기존 네트워크의 물리적인 구조 및 구성을 변경하지 않고 네트워크 보안을 도입할 수 있는 방안으로 "Man In The Middle Attack" 공격 기법을 역이용함으로, Single Ethernet Interface만으로 가상 네트워크 오버레이를 형성하여 논리적인 In-line Mode를 구현하여 외부의 공격으로부터 네트워크를 보호하는 초소형 네트워크 보안 센서와 클라우드서비스를 통한 통합관제 방안을 제안한다. 실험 결과, Single Ethernet Interface만으로 가상 네트워크 오버레이를 형성하여 논리적인 In-line Mode를 구현할 수 있었으며, Network IDS/IPS, Anti-Virus, Network Access Control, Firewall 등을 구현할 수 있었고, 초소형 네트워크보안센서를 클라우드서비스에서 통합관제하는 것이 가능했다. 본 논문의 제안시스템으로 저비용으로 고성능의 네트워크 보안을 기대하는 중소기업에 도움이 되고 또한, IoT 및 Embedded System 분야에 안전·신뢰성을 갖춘 네트워크 보안환경을 제공할 수 있다.

• 한국음향학회지
• /
• 제27권1호
• /
• pp.40-46
• /
• 2008

천해 영역에서 선박과 같은 수상 소음원의 간섭 신호는 정합장처리를 이용한 수중 표적 탐지 및 위치추정 기법 적용에 있어 문제점으로 남아있다. 정지 음원의 경우 수신기공간의 음장에 대한 고유벡터분해를 통해 각 음원 성분을 분리하고 간섭 신호 성분을 제거할 수 있다. 하지만 일반적인 이동 음원 환경에서는 각 신호 성분의 에너지가 수신 음장의 부분공간에 퍼지게 되므로, 고유값 분포 비교만으로 각 신호 성분을 구별하기 어렵게 되거나 하나의 고유벡터에 각 신호성분이 섞이는 경우도 발생한다. 본 논문에서는 수상 음원과 수중 음원 신호의 물리적 특성 차이를 이용한 모드공간 간섭 신호 제거 기법을 제안하였다. 이 기법은 모드-공분산행렬에 대한 고유벡터분해를 통해 간섭 신호 성분을 판별하며, 이 성분들을 부분공간에서 제거함으로써 차폐되었던 표적 신호를 복원하고 위치추정을 가능하게 한다. 이를 모의실험을 통해 확인하고 결과에 대해 논의하였다.

• 대한임상전기생리학회지
• /
• 제5권1호
• /
• pp.1-10
• /
• 2007

This study aims to comparison of ultrasonography on both sides of the upper arm of hemiplegic patient. The biceps brachii and deltoid muscle of ten subjects(4 men, 6 women) with stroke were scanned with ultrasonography at the muscle belly at rest at elbow angles of 90 deg. The echogenicity(densit, white area index; WAI) and muscle thickness of ultrasonography was examined using real-time B-mode ultrasonography with 7.5 MHz linear-array prob. In the biceps brachii muscle, MHz there were significant differences of thickness, density, and WAI between affected side and non-affected side. In the deltoid muscle, there were significant differences of thickness, density, and WAI between affected side and non-affected side. Both of the muscles, thickness of the affected side was thin than non-affected side and echogenicity(density, WAI) of the affected side was higher than non-affected side. This study showed that change of skeletal muscle architecture properties occurred in the upper arm of the affected side muscle of hemiplegic patient.

• 대한임상전기생리학회지
• /
• 제5권1호
• /
• pp.11-20
• /
• 2007

The purpose of this study were to analysis on quality properties of lower extremity of patient with stroke by the existence of the independent walking. We recruited fourteen adults after stroke(7 male, 7 female; mean age, 64y) for our study. The subjects were divided into two groups; independent walking group(3 male, 3 female) and non-independent walking group(4 male, 4 female). We used in this study included a B-mode ultrasonography scanner with a 7.5 MHz linea probe. During the experiment, the subject was seated in the chair. The echogenicity(density, white area index; WAI) of the tibialis anterior and rectus femoris muscles were measured on both sides of the leg. In both of the density and WAI, the tibialis anterior muscle were significant differences between paratic side and non-paratic side, the independent walking and non-independent walking group. However, in both of the density and WAI of the rectus femoris muscle were only significant differences between paratic side and non-paratic side. This study showed that stroke and the independent walking have influenced on quality properties of lower leg. Especially, the independent walking has influenced on the tibialis anterior muscle.

• 대한물리치료과학회지
• /
• 제9권2호
• /
• pp.133-141
• /
• 2002

This purpose of this study was to design the effect of recovering of a hand amputees by Myoelectronic hand. It was designed with 2 degree of freedom in the laboratory. Myoelectronic hand had only one degree of freedom and one movement until now. Also this myoelectronic hand had multi-joint and it could move widely. Wire was used in transmission. Myoelectronic hand data was obtained by analyzing hand anatomically and measuring and that data was applied when it was designed. PID controller of Myoelectronic hand was used to it. Displacement control was applied the first link. Experiment was accomplished in Tip grasp, Power grasp and Hook grasp modes. Displacement control was good in low frequency. Velocity control was applied to each mode. The objective of the study was to develop more better multifunction myoelectronic control strategies. A myoelectronic hand with a hand amputees could do some jobs such as grasping materials, lifting weighting, holding cup and etc. As a result of this study, all subjects with hand amputees significantly improved in ADL. Further studies were needed to evaluate the effect of a myoelectronic hand with more precise laboratory equipment.

• 대한물리치료과학회지
• /
• 제7권2호
• /
• pp.697-709
• /
• 2000

이 실험의 목적은 Electro-Myoscope 이 과다 사용에 의해 일어나는 대퇴사두 근육 통증에 미치는 효과에 대해 근전도를 이용한 연구입니다. 이를 위해 나이 15세부터 50세 사이의 18명의 여성 자원자들이 참여했다. 대퇴직근을 Cybex 운동기기를 사용해 Terminal knee extension 운동을 통해 과다사용으로 인한 통증이 유발되게 하였다. 그리고, Electro-Myoscope을 치료 후 근전도를 통해 대퇴사두근의 motor recruit 에 대해 기록 비교하였다. t-test 와 Chi square 분석 결과 대퇴사두근의 기능이 향상된 것으로 나타났다.

• 천문학회지
• /
• 제48권3호
• /
• pp.165-175
• /
• 2015

We investigate physical properties of the nearby (∼ 7.5 pc) astrometric binary μ Cas in the context of standard evolutionary theory. Based on the spectroscopically determined relative abundances ([α/Fe] ≳ +0.4 dex, [Fe/H] ∼ −0.7 dex), all physical inputs such as opacities and equation of state are consistently generated. By combining recent spectroscopic analyses with the astrometric observations from the HIPPARCOS parallaxes and the CHARA array, the evolutionary model grids have been constructed. Through the statistical evaluation of the χ²-minimization among alternative models, we find a reliable evolutionary solution (M_A, M_B, t_age) = (0.74 M_⊙, 0.19 M_⊙, 11 Gyr) which excellently satisfies observational constraints. In particular, we find that the helium abundance of μ Cas is comparable with the primordial helium contents (Y_p ∼ 0.245). On the basis of the well-defined stellar parameters of the primary star, the internal structure and the p-mode frequencies have been estimated. From our seismic computation, μ Cas is expected to have a first order spacing ∆ν ∼ 169 μHz. The ultimate goal of this study is to describe physical processes inside a low-mass star through a complete modelling from the spectroscopic observation to the evolutionary computation.

• 센서학회지
• /
• 제27권1호
• /
• pp.59-63
• /
• 2018

Among Internet of things (IoT) applications, the most demanding requirements for the widespread realization of many IoT visions are security and low power. In terms of security, IoT applications include tasks that are rarely addressed before such as secure computation, trusted sensing, and communication, privacy, and so on. These tasks ask for new and better techniques for the protection of data, software, and hardware. An integral part of hardware cryptographic primitives are secret keys and unique IDs. Physical Unclonable Functions(PUF) are a unique class of circuits that leverage the inherent variations in manufacturing process to create unique, unclonable IDs and secret keys. In this paper, we propose a low power Arbiter PUF circuit with low error rate and high reliability compared with conventional arbiter PUFs. The proposed PUF utilizes a power gating structure to save the power consumption in sleep mode, and uses a razor flip-flop to increase reliability. PUF has been designed and implemented using a FPGA and a ASIC chip (a 0.35 um technology). Experimental results show that our proposed PUF solves the metastability problem and reduce the power consumption of PUF compared to the conventional Arbiter PUF. It is expected that the proposed PUF can be used in systems required low power consumption and high reliability such as low power encryption processors and low power biomedical systems.

• Nuclear Engineering and Technology
• /
• 제45권5호
• /
• pp.653-664
• /
• 2013

The design of computer-based instrumentation and control (I&C) systems is determined by the allocation of I&C functions to I&C systems and components. Due to the characteristics of computer-based technology, component failures can negatively affect several I&C functions, so that the reliability proof of the I&C systems requires the accomplishment of I&C system design analyses throughout the I&C life-cycle. On one hand, this paper proposes the restructuring of the sequential IEC 61513 I&C life-cycle according to the V-model, so as to adequately integrate the concept of verification and validation. On the other hand, based on a metamodel for the modeling of I&C systems, this paper introduces a method for the modeling and analysis of the effects with respect to the superposition of failure combinations and event sequences on the I&C system design, i.e. the temporal change of physical structure is analyzed. In the first step, the method is concerned with the modeling of the I&C systems. In the second step, the method considers the analysis of temporal change of physical structure, which integrates the concepts of the diversity and defense-in-depth analysis, fault tree analysis, event tree analysis, and failure mode and effects analysis.