• 한국광학회지
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• 제8권4호
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• pp.340-344
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• 1997

기존의 광섬유 격자 소자를 이용한 광 분기/결합 장치들이 광섬유 격자 소자의 브래그 파장에 해당하는 신호만을 선택할 수 있었던 단점을 극복하기 위해 압전 소자에 광섬유 격자 소자를 부착한 압전 소자형 광섬유 격자 소자를 제작하고, 이러한 압전소자형 광섬유 격자 소자와 편광 선속분할기를 이용하여 파장 분할 다중화 시스템용 파장 가변형 광 분기/결합 장치를 제안하고 실험하였다. 본 장치는 두 빛의 편광 상태를 이용하여 광섬유 격자 소자에 해당하는 파장의 신호를 분기/결합하는 장치로서 외부의 온도 변화에 크게 영향을 받지 않는 안정적인 특성을 보였다. 압전 소자에 전압을 인가함으로써 광섬유 격자 소자의 브래그 파장에 해당되는 신호(1549.3 nm)뿐만 아니라 가변된 파장(1550.1 nm)의 신호도 분기/결합할 수 있었다. 파장을 가변하지 않을 경우와 파장을 가변했을 경우 모두 광섬유 격자 소자에 의해 분기된 신호와 인접 채널 신호간의 차이 -26 dB 이하였으며 분기된 신호 중 광섬유 격자 소자를 통해 나오는 누설 신호는 -34 dB였다.

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.106-112
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• 2017

The present study describes flow induced noise generated from a ball valve used for a gas pipeline. Noise generation from a ball valve mainly induces by interference between unstable(or fluctuating) leakage flow and pipe wall when the ball valve is working closed or opened. To measure the positions of the noise source and the amplitude of noise with respect to measuring frequencies, a commercial acoustic camera is introduced. Noise characteristics generated by the ball valve have been performed by four valve opening rates: 30, 50, 70 and 100 percents. It is noted that 100 percent opening rate means that the valve is fully opened. Throughout the experimental measurements using the acoustic camera, the location of the noise source and the noise amplitude with respect to the frequencies for the test ball valve are clearly evaluated. It is found that the dominant frequencies come from the fluctuating flow at the downstream of the ball valve for four opening rates are observed between 3,000Hz and 3,200Hz. Maximum noise amplitude comes from the ball valve reaches 75dB at the valve opening rate of 50 percent.

• 한국전기전자재료학회논문지
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• 제25권2호
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• pp.100-104
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• 2012

Fin-type SONOS (silicon-oxide-nitride-oxide-silicon) flash memory has emerged as novel devices having superior controls over short channel effects(SCE) than the conventional SONOS flash memory devices. However despite these advantages, these also exhibit undesirable characteristics such as corner effect. Usually, the corner effect deteriorates the performance by increasing the leakage current. In this paper, the corner effect of fin-type SONOS flash memory devices is investigate by 3D Process and device simulation and their electrical characteristics are compared to conventional SONOS devices. The corner effect has been observed in fin-type SONOS device. The reason why the memory characteristic in fin-type SONOS flash memory device is not improved, might be due to existing undesirable effect such as corner effect as well as the mutual interference of electric field in the fin-type structure as reported previously.

• 한국자동차공학회논문집
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• 제20권4호
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• pp.109-118
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• 2012

Large number of part design for aircraft and automobile is preceded by functional or sectional design groups for efficiency. However, interferences and gaps can be found when the parts and sub-assemblies by those design groups are to be assembled. These interferences and gaps cause design changes and additional repair processes. While interference problem has been resolved by digital mockup and concurrent engineering methodology, gap problem has been covered by temporary treatment of filling gap with sealant. This kind of fast fix causes fatal problem of leakage when the gap is too big for filling or the treatment gets old. With this research, we have developed a program to find the gap automatically among parts of assembly so that users can find them to correct their design before manufacturing stage. By using decomposition model representation method, the developed program can search the gap among complex car body parts to be visualized with volumetric information. It can also define the boundary between the gap and exterior empty space automatically. Though we have proved the efficiency of the developed program by applying to automobile assembly, application of the program is not limited to car body only, but also can be extended to aircraft and ship design of large number of parts.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.193-197
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• 2004

The organic light emitting diode (OLED) is proposed as the novel source in the microchip because it has ideal merits (various wavelengths, thin-film structure and overall emitting) for the integration. In this paper, we fabricated the finger-type pin photodiodes for fluorescence detection and the advanced microchip with OLED integrated pn the microchannel. The finger-type in the diode design extended the depletion region and reduced the internal resistance about 31.2% than rectangular-type. The photodiodes had a 100pA leakage current and a 8720 sensitivity $(I_{Light}/I_{Dark})$ at -1 V bias. The interference filter with 32 layers ($SiO_2$, $TiO_2$) was directly deposited on the photodiode. The OLED was fabricated on the ITO coated glass and was bonded with LOC. The application of thin-film OLED increased the excitation efficiency and simplified the integration process extremely. The prototype device of this application had a superior sensitivity of 100nM-LOD in the fluorescence detection.

• 한국자동차공학회논문집
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• 제15권4호
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• pp.10-16
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• 2007

A rubber seal for wheel bearing which has been mainly applied to car wheel supporting device is required to have both high sealing performance and drag torque. Because of severe operational conditions like infiltration of mud or splashed water, the importance of rubber seal which is aimed for leakage prevention of grease and effective blocking of foreign substances has been increasing continuously. The sealing performance of this seal depends on several factors such as materials of seal, friction conditions of contact regions and geometry of seals and so on. We have focused on the effects of geometric characteristics such as the angle of main lip, interference between lip edge and inner metallic ring. In this study, the optimization of geometric variables was performed using the finite element analysis. For the sake of finite element analysis, uniaxial tensile tests were conducted and several constants for Mooney-Rivlin's equation were obtained. According to the results of this study, mock-up bearing was made. To verify this study, drag torque and mud spray test were preformed.

• 한국전자파학회논문지
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• 제23권7호
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• pp.791-796
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• 2012

RF 리미터(limiter)는 원하지 않는 신호로부터 수신단을 보호하기 위해 사용되는 소자로서, 임계값 이상의 모든 입력신호에 대해 일정한 출력을 제공한다. 다이오드를 사용하는 RF 리미터는 작은 신호는 통과시키는 반면, 어떤 임계값 이상의 신호는 감쇄시켜서 전달한다. 현대의 레이더 시스템에서 수신기를 보호하기 위해 사용되는 RF 리미터는 새로운 간섭 위협이나 복잡한 전자파 환경의 도전으로부터 극복할 수 있는 절대 필요한 역할을 수행한다. 본 논문은 고출력 RF 리미터를 구현하기 위해 PIN 다이오드와 Limit 다이오드의 조합으로 구성된 회로를 제안한다. PIN 다이오드는 스위치의 격리도(isolation) 특성을 이용하는 것과 같이 다이오드의 격리도 특성을 이용하는 개념을 적용한다. S-대역에서 200 us 펄스폭을 갖는 2 kW RF 리미터를 개발하였다. 그 측정 결과는 예측한 값과 잘 일치함을 알 수 있다.

• Ocean and Polar Research
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• 제42권3호
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• pp.195-210
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• 2020

The observed time series from the Korea Ocean Research Stations (KORS) in the Yellow and East China Seas (YECS) have various sources of noise, including bio-fouling on the underwater sensors, intermittent depletion of power, cable leakage, and interference between the sensors' signals. Besides these technical issues, intricate waves associated with background tidal currents tend to result in substantial oscillations in oceanic time series. Such technical and environmental issues require a regionally optimized automatic quality control (QC) procedure. Before the achievement of this ultimate goal, we examined the approach of the Ocean Observatories Initiative (OOI)'s standard QC to investigate whether this procedure is pertinent to the KORS. The OOI QC consists of three categorized tests of global/local range of data, temporal variation including spike and gradient, and sensor-related issues associated with its stuck and drift. These OOI QC algorithms have been applied to the water temperature time series from the Ieodo station, one of the KORS. Obvious outliers are flagged successfully by the global/local range checks and the spike check. Both stuck and drift checks barely detected sensor-related errors, owing to frequent sensor cleaning and maintenance. The gradient check, however, fails to flag the remained outliers that tend to stick together closely, as well as often tend to mark probably good data as wrong data, especially data characterized by considerable fluctuations near the thermocline. These results suggest that the gradient check might not be relevant to observations involving considerable natural fluctuations as well as technical issues. Our study highlights the necessity of a new algorithm such as a standard deviation-based outlier check using multiple moving windows to replace the gradient check and an additional algorithm of an inter-consistency check with a related variable to build a standard QC procedure for the KORS.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.183-183
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• 2014

Recently, multiferroic materials gain much attention due to their fascinating fundamental physical properties. These materials offer wide range of potential applications such as data storage, spintronic devices and sensors, where both electronic and magnetic polarizations can be coupled. Among single-phase multiferroic materials, $BiFeO_3$ is typical because of the room-temperature magnetoelectric coupling in view of long-range magnetic- and ferroelectric-ordering temperatures. However, $BiFeO_3$ is well known to have large leakage current and small spontaneous polarization due to the existence of oxygen vacancies and other defects. Furthermore the magnetic moment of pure $BiFeO_3$ is very weak owing to its antiferromagnetic nature. Recently, various attempts have been performed to improve the multiferroic properties of $BiFeO_3$ through the co-doping at the A and the B sites, by making use of the fact that the intrinsic polarization and magnetization are associated with the lone pair of $Bi^{3+}$ ions at the A sites and the partially-filled 3d orbitals of $Fe^{3+}$ ions at the B sites, respectively. In this study, $BiFeO_3$, $Bi_{0.9}Ho_{0.1}FeO_3$, $BiFe_{0.97}Ni_{0.03}O_3$ and $Bi_{0.9}Ho_{0.1}Fe_{0.97}Ni_{0.03}O_3$ bulk compounds were prepared by solid-state reaction and rapid sintering. High-purity $Bi_2O_3$, $Ho_2O_3$, $Fe_2O_3$ and $NiO_2$ powders with the stoichiometric proportions were mixed, and calcined at $500^{\circ}C$ for 24 h to produce the samples. The samples were immediately put into an oven, which was heated up to $800^{\circ}C$ and sintered in air for 1 h. The crystalline structure of samples was investigated at room temperature by using a Rigaku Miniflex powder diffractometer. The field-dependent and temperature-dependent magnetization measurements were performed with a vibrating-sample magnetometer and superconducting quantum-interference device.

• 시큐리티연구
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• 제2호
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• pp.99-123
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• 1999

Internet related crimes are a crime which is inter-related with high specialization ${\cdot}$ technicality ${\cdot}$ leakage of information ${\cdot}$ intellectual-offence and deviant behavior. Without the accurate countermeasure, we can't achieve the desired end. So we should find out multilateral and general measure. Always crimes go in advance of the measure, so the counter measures against, computer crime can not be final. Nevertheless, we can't be careless in making the measure, but we should always consider a counter measure. 1995. 12. 29. our country revised criminal law and consolidated direct provisions, especially on the computer-hacking. But, inspite of the revision, especially on the computer-hacking. But, inspite of the revision, we have many problems'. So, first of all, through the positive and empirical study, we should revise criminal law and computer crime related provisions systematically. As the aspects and techniques of internet related crimes are always changing with the development of computer technology, there will be many problems with principle of legality, when we apply the existing abstract provisions to the new crime. We can not be lazy in studying the emerging internet related crimes and taking concrete shape of the provision. And it will be a big help to that desirable to import the foreign provision without consideration of our reality. Without the positive and empirical study on internet related crimes, sometimes important crime will be out of reach of the punishment. Due to these day's development of computer and technology of communication, the personal computers are widely supplied and especially PC communication and exchange of the informations became the most important function. With the advent of internet, new aspects of crimes are appearing. Up to now, the fraud by using the computer or the interference in the execution of duty by the illegal operation of computer was the leading aspects of computer crime, but nowadays with the advent of internet, database crime or network crime like the computer hacking became the important aspects of internet related crimes. These new aspects of internet related crimes are defusing into domains of traditional crimes. Nevertheless to follow and punish the acts on the internet is not technically easy, and as it is emerging international shape, to settle it by international law is not that easy. Harmful acts in the information-oriented society are very diverse in kinds and aspects, and it is difficult to enumerate. The point is that among the new acts in the information-oriented society we should decide which acts are to be punished and which acts are not to be punished. It is needless to say that the criminal law should be the last resort. But owing to the characters of the characteristics of the information-oriented society, when the traditional standards can be applied, the question of what is the basis and how it can be applied in a concrete way is not settled. And if it cannot be applied, how can we make new standard is also an unsettled question.