• 한국대기환경학회지
• /
• 제26권4호
• /
• pp.449-452
• /
• 2010

In this article, the performance of the THC analyzer was inspected using two different span gases of methane ($CH_4$) and propane ($C_3H_8$). To explore the effect of standard gas selection, MicroFID system was tested by the following procedures. Initially, the system is spanned by propane gas of 60 ppm (or 180 ppmC). The system is then run against methane standards prepared at 5 different concentrations of 200, 250, 300, 400, and 500 ppm. According to the suggestion of the KMOE's test procedure to use multiplying a factor of 3 (for propane), the resulting THC values derived by methane standards were systematically biased with ~500% error relative to true value. This paper discusses the interpretation procedures to obtain the least biased THC values for a given span set-up.

• 한국초전도ㆍ저온공학회논문지
• /
• 제16권4호
• /
• pp.17-20
• /
• 2014

We have investigated the effect of temperature and bias current on the stability of the inverse spin-switch effect in Permalloy(Py)/Nb/Permalloy pseudo spin-valves. The inverse spin-switch operates between two orientations of the ferromagnetic moments of Py layers; parallel (ON) and antiparallel-domain (OFF) state. Measuring time scans of the resistance changes between the ON and OFF state, ${\Delta}R_{ON-OFF}$, while alternating magnetic fields between the two states at various temperatures and bias currents, revealed that enhancement of ${\Delta}R_{ON-OFF}$ is a key factor to achieve successful operation of superconducting spin switch.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제49권9호
• /
• pp.527-532
• /
• 2000

The performance of ac plasma display panels (PDP) is influenced strongly by the surface glow discharge characteristics on the MgO thin films. This paper deals with the surface glow discharge characteristics and some physical properties of MgO thin films prepared by reactive RF planar unbalanced magnetron sputtering in connection with ac PDP. The samples prepared with dc bias voltage of -10V showed lower discharge voltage and lower erosion rate byion bombardment than those samples prepared by conventional magnetron sputtering or E-beam evaporation. The main factor that improves the discharge characteristics by bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardement during deposition process.

• 한국표면공학회지
• /
• 제31권5호
• /
• pp.245-250
• /
• 1998

There is clear pressing need to reduce bias field(Ha,) used on linear magenetomechanical resonator tag by at least a factor of two to allow low-bias operation near the frequency minimum since reducing Ha causes a dramatic increase in well depth, which implies increased stability. However, this makes it more difficult to maintain tight frequncy specs. It can be solved by a reduction of magnetomechanical coupling(k). We determined from an equivalent circuit model that optimal reduced, k, is near 0.3 Also, We determiend the material properties($lambda_s$, :saturated magenetostriction, $M_s$, and,$H_a$) that give k=0.3. From these evaluations, we suggested that on optimal comosition with adequate mathrial properties is $Fe_{55}Co_{15}Cr_6Nb_2B_{18}Si_4$.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.64.2-64
• /
• 2001

In this paper, fabricated is a motion capture and attitude detection system for Head Mounted Display HMD composed of three low-price and low-grade micro gyroscopes and a micro-controller, To calculate attitude of a body, modified INS algorithm is used. Because the micro gyroscope has much bias drift error, scale factor error, and run-to-run bias error, the motion of a body can not be measured exactly if the general INS algorithm and micro gyroscopes are used. To reduce the errors, three accelerometers can be used. In this case, however, the size and power consumption become too large to use in HMD system. The modified INS algorithm use the grid map and the characteristics of the human motions.

• 한국컴퓨터정보학회논문지
• /
• 제25권7호
• /
• pp.159-165
• /
• 2020

비대칭적 원가행태가 발생하는 원인에 관한 연구는 크게 두 가지로 흐름으로 구분된다. 하나는 경영자의 기대적 관점이고 다른 하나는 대리인 관점에서 이를 설명한다. 본 연구에서는 선행연구의 두 가지 관점을 확장하여 기업의 비대칭적 원가행태를 결정하는 요인이 무엇인지 구체적으로 살펴보고자 한다. 먼저 경영자의 낙관적 기대오류가 비대칭적 원가행태에 미치는 영향을 분석하고, 다음으로 경영자지분율이 높은 상황의 기업지배구조가 비대칭적 원가행태에 어떠한 영향을 미치는지 분석하였다. 분석결과는 다음과 같다. 첫째, 우리나라 기업은 하방탄력적 구조의 비대칭적 원가행태를 가진다. 둘째, 미래 수요에 대한 경영자의 낙관적 기대오류를 가진 기업은 이러한 비대칭적 원가행태가 완화되는 것으로 나타났다. 이는 경영자의 낙관주의가 기업의 원가의사결정에 영향을 미치는 요인임을 의미한다. 셋째, 경영자지분율이 높은 기업 역시 비대칭적 원가행태가 완화됨을 확인하였다. 이는 경영자의 원가의사결정에 지배구조가 중요한 역할을 하고 있음을 알려주는 실증적 결과라 하겠다.

• 한국전기전자재료학회논문지
• /
• 제19권9호
• /
• pp.818-824
• /
• 2006

The effects of high-temperature process required to fabricate the SiC devices on the surface morphology and the electrical characteristics were investigated for 4H-SiC Schottky diodes. The 4H-SiC diodes without a graphite cap layer as a protection layer showed catastrophic increase in an excess current at a forward bias and a leakage current at a reverse bias after high-temperature annealing process. Moreover it seemed to deviate from the conventional Schottky characteristics and to operate as an ohmic contact at the low bias regime. However, the 4H-SiC diodes with the graphite cap still exhibited their good electrical characteristics in spite of a slight increase in the leakage current. Therefore, we found that the graphite cap layer serves well as the protection layer of silicon carbide surface during high-temperature annealing. Based on a closer analysis on electric characteristics, a conductive surface transfiguration layer was suspected to form on the surface of diodes without the graphite cap layer during high-temperature annealing. After removing the surface transfiguration layer using ICP-RIE, Schottky diode without the graphite cap layer and having poor electrical characteristics showed a dramatic improvement in its characteristics including the ideality factor[${\eta}$] of 1.23, the schottky barrier height[${\Phi}$] of 1.39 eV, and the leakage current of $7.75\{times}10^{-8}\;A/cm^{2}$ at the reverse bias of -10 V.

• Nuclear Engineering and Technology
• /
• 제18권1호
• /
• pp.17-26
• /
• 1986

연소를 고려하는 사용후핵연료저장조의 핵임계 안전성 분석에서 검증용 계산 체제와 rack계산 체제 사이의 편차를 신뢰성 있게 결정하는 방법을 시험하였다. 이를 위하여 고리 1호기의 사용후핵연료저장조를 연소를 고려하는 가장 조밀한 rack으로 개념설계하고, 핵연료의 농축도 및 연소도에 따라 증배계수를 계산하였다. 표준값 생산용 Monte Carlo 코드로는 KENO-IV를 그리고 실제 rack 설계용으로는 2차원 충돌화률 코드인 FATAC을 사용하였다. 이 두 계산의 결과를 상호 비교하여 계산 체제 사이의 편차와 이의 경향성 및 신뢰도를 평가하였다. 이 방법을 사용하면 확실한 신뢰도 근거를 마련할 수 있을 뿐만 아니라 반응도 여유면에서 기존의 방법보다 불리하지 않음이 입증되었다.

• 수산경영론집
• /
• 제47권3호
• /
• pp.71-92
• /
• 2016

This study examines the effects of consumer beliefs for food certifications on the behavioral intentions and the behavioral intention biases to purchase the certified seafoods by a subjective probability model which is on the basis of the mathematical probability model and the covariance model. The food certifications used on this study are 'Organic foods', 'Traceability system of food products' and. 'HACCP'. The representative foods of fishery products on this study is seasoned laver. The current study showed the following results. First, consumers have more than two different beliefs each for all certifications which are the subjects of this study. The beliefs of the certifications have an impact on the consumers when they consider to buy the certified seafood products. Second, consumers try to persuade by themselves to ensure that their particular belief about the certification could lead to a purchase the seafood products. Consumer beliefs of the "environmentally friendly production" on the organic foods certification is an important factor as much as the "guarantee of food safety" belief making a positive purchasing behavior intentions(PBI) bias for the organic seafood products. Consumers also have a positive PBI bias for certified seafood products in all certifications as long as a certification is considered to "guarantee the transparency of the food distribution process" as its belief. 'Traceability system' was the only one which didn't generate a positive PBI bias from the belief of "guarantee of food safety" out of three certifications.

• 대한교통학회지
• /
• 제14권1호
• /
• pp.29-42
• /
• 1996

Among trip distribution models, The BPR type Gravity Model is the one which is the most widely used. The key issue associated with this model is a functional form of friction factor which should be calibrated in the process, and interpretation for socioeconomic factor known as K-factor(Kij) which is used to adjust the difference between observed zone-to-zone trips and the estimated trips. In this study, the BPR type Gravity Model has been fitted to 1990 O/D data for Seoul. Two type of function form for friction factor has been employed : one is a form of Generalized function and the orther is UTP function. With above two function, the parameters for travel distance(Skin-tree) are prepared. The relationship between socioeconomic factor and trips is identified by calculating and analyzing the characteristics of Kij. Consequently, both of the friction factor functions are statistically signified. However, it show an overestimation tendency when estimated with UTP function. It is found that the Generalized function is suitable for the city of Seoul, and also, in case there are a lot of trips correlatively, the socioeconomic factor is close to 1, on the other hand if it's small, it shows a bias which is dispersed around 1.