• Journal of information and communication convergence engineering
• /
• 제18권3호
• /
• pp.201-206
• /
• 2020

This paper presents a new method for controlling the current of lighting LEDs without current sensors. This method can be used as backup against LED current sensor faults. LED lighting requires a circuit with a constant current in order to maintain the same brightness when the ambient temperature changes. Therefore, we propose a new current estimation method to provide backup in case of current sensor faults based on the calculation of the inductor current. In the fabricated circuit, the average current changes from 144.03 mA to 155.97 mA when the ambient temperature changes from 0℃ to 60℃. The application of this study can enable the fabrication of a driving IC for LEDs in the form of a single chip without sensing resistors. This is expected to reduce the complexity of the peripheral circuit and enable precise feedback control.

• 동의생리병리학회지
• /
• 제16권5호
• /
• pp.873-880
• /
• 2002

We study on the significance and application of the whole body form diagnosis. The results were as follows; The general form diagnosis is the method to observe the individual physiology and pathology. The phase of thinking, the current and activity of KI, the pattern of general form diagnosis have organic relations with the symptoms. The general form diagnosis is made up the principle of the imaging phase, therefore it must make synthetic union the differentiation of syndromes. The general form diagnosis of NAE GYEONG shows the typical phases and it is divided with the sight of YIN YANG and Five-Element. The general form diagnosis of SEOP GAE is practiced the theory of constitution's demonstration before the understanding of symptoms. Then JANG NAM tried the type of constitution's demonstration. The general form diagnosis of DONG MU becomes the diagnostic root of constitution's demonstration in four type constitution theory.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 추계 학술논문 발표대회
• /
• pp.4-5
• /
• 2019

With recent advances in computer technology, the ratio of free-form building designs to those of the past is increasing gradually. However, the current technology of free-form structure is very low. The core technology for free-form building implementation is the manufacturing technology of FCP (Free-form Concrete Panel), which indicates an unformed outside, and through the development of FCP manufacturing technology, the construction technology of free-form architecture can be enhanced. The inside and outside of an free-form building should be represented by the designer's intended curvature, and the panel's thickness by segment should be constant. For this reason, the technology that keeps the thickness of panels constant during the FCP production process is a key technology that can improve the quality of FCP. In this study, a basic study on ways to maintain a constant thickness of FCP is conducted.

• Ocean and Polar Research
• /
• 제42권3호
• /
• pp.211-223
• /
• 2020

With the increasing demand for improved marine environments and safety, greater ability to minimize damages to coastal areas from harmful organisms, ship accidents, oil spills, etc. is required. In this regard, an accurate assessment and understanding of current systems is a crucial step to improve forecasting ability. In this study, we examine spatial and temporal characteristics of current systems in the adjacent seas of Jeju Island using a high-resolution regional ocean circulation model. Our model successfully captures the features of tides and tidal currents observed around Jeju Island. The tide form number calculated from the model result ranges between 0.3 and 0.45 in the adjacent seas of Jeju Island, indicating that the dominant type of tides is a combination of diurnal and semidiurnal, but predominantly semidiurnal. The spatial pattern of tidal current ellipses show that the tidal currents oscillate in a northwest-southeast direction and the rotating direction is clockwise in the adjacent seas of Jeju Island and counterclockwise in the Jeju Strait. Compared to the mean kinetic energy, the contribution of tidal current energy prevails the most parts of the region, but largely decreases in the eastern seas of Jeju Island where the Tsushima Warm Current is dominant. In addition, a Lagrangian particle-tracking experiment conducted suggests that particle trajectories in tidal currents flowing along the coast may differ substantially from the mean current direction. Thus, improving our understanding of tidal currents is essential to forecast the transport of marine pollution and harmful organisms in the adjacent seas of Jeju Island.

• Structural Engineering and Mechanics
• /
• 제88권2호
• /
• pp.159-168
• /
• 2023

Cost-effective high precision hybrid elements are presented in a hierarchical form for dynamic analysis of plates. The costs associated with controlling the vibrations of ferromagnetic plates can be minimized by adequate determination of the amount of electric current and magnetic field. In the present study, the effect of magnetic field and electric current on nonlinear vibrations of ferromagnetic plates is investigated. The general form of Lorentz forces and Maxwell's equations have been considered for the first time to present new relationships for electromagnetic interaction forces with ferromagnetic plates. In order to derive the governing nonlinear differential equations, the theory of third-order shear deformations of three-dimensional plates has been applied along with the von Kármán large deformation strain-displacement relations. Afterward, the nonlinear equations are discretized using the Galerkin method, and the effect of various parameters is investigated. According to the results, electric current and magnetic field have different effects on the equivalent stiffness of ferromagnetic plates. As the electric current increases and the magnetic field decreases, the equivalent stiffness of the plate decreases. This is a phenomenon reported here for the first time. Furthermore, the magnetic field has a more significant effect on the steady-state deflection of the plate compared to the electric current. Increasing the magnetic field and electric current by 10-times results in a reduction of about 350% and an increase of 3.8% in the maximum steady-state deflection, respectively. Furthermore, the nonlinear frequency decreases as time passes, and these changes become more intense as the magnetic field increases.

• 조명전기설비학회논문지
• /
• 제19권8호
• /
• pp.102-108
• /
• 2005

본 논문에서는 소프트 스위칭에 의한 새로운 고역률 승압형 AC-DC 컨버터가 제안되고 입력전류의 파형 및 고조파분석에 대해 상세히 해석된다. 시비율 일정의 전류불연속 제어에 의해 동작되는 제안된 컨버터의 입력전류는 교류 입력전압의 크기에 비례한 불연속적인 펄스열의 정현파 형태로 되어 입력역률을 개선시킨다. 또한 제안된 컨버터는 소프트 스위칭을 위한 공진동작에 의해 무손실 스너버 커패시터의 입력측 에너지 유입에 따른 역률증대의 효과를 가지며, 기존의 고역률 승압형 AC-DC 컨버터와 비교되어 입력전류의 수학적 분석과 컴퓨터 시뮬레이션, 실험결과 등에 의해 그 우수성이 입증된다.

• 한국표면공학회지
• /
• 제27권6호
• /
• pp.340-346
• /
• 1994

The method of uniforming current distribution in Hull cell are studied by using auxiliary anode, current shield bipolar electrode, and combinings bipolar electrode with current shield in order to find a way of uni-form deposition. The current density distributions are measured by each ammeter of the same inner resistance connected to divided cathode pannel respectively. The current density distributions of cathode electrode divided into five sections with 5mm width have a tendency of linear inclination, and that of twenty sections have a tendency of smoother curve than the curve of original Hull cell pannel. Their results showed lower value on the high current density portion and higher value on the low portion than that original Hull cell pannel. The current distribution in Hull cell is able to unify by using auxiliary anode, or combining bipo-lar electrode with current shield, but not efficient in using one of both individually.

• 한국통신학회논문지
• /
• 제13권3호
• /
• pp.255-259
• /
• 1988

무한히 긴 도체 스트립라인으로 이루어직 격자위에 TM파가 입사될 때 전류분포를 계산한다. 이런 구조에 모먼트법을 적용하면 행렬식이 매우 커져서 큰 컴퓨터 용량과 많은 계산시간이 필요하게 된다. 격자들의 경계조건과 산란파를 스펙트럴 영역으로 변환하고 격자들의 주기적 구조를 이용하여 Flouquet모드를 적용하며 산란파는 급수형태로 변형될 수 있다. 적합한 전개함수를 선정하여 급수형태의 식을 행렬로 변형하면 도체 스트립에 발생된 전류분포를 계산할 수 있다. 입사파의 각도 변화와 스트립의 폭과 간격의 변화에 따른 전류분포를 계산하다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
• /
• pp.699-702
• /
• 2002

A DC current sensor is disclosed in which two pairs of saturable cores are provided so as enclose a conductor carrying a direct current to be measured. On each of the saturable cores, a bias winding, a feedback winding and an output winding are wound. Circuit for detection of an asymmetry in the magnetization current, generated by a reference alternating voltage, in a signal-conditioner. The reference alternating voltage is fed to the respective series circuits such that no resultant induction current is induced in the modulating current. The voltages over the resistor form input signals for two peak value detectors, the strength of the output signal of which represents the degree of asymmetry of magnetization current. This paper describes the development a DC current sensor and its signal-conditioner.

• 센서학회지
• /
• 제23권2호
• /
• pp.114-121
• /
• 2014

We report a polysilicon active area membrane field effect transistor (PSAFET) pressure sensor for low stress deflection of membrane. The PSAFET was produced in conventional FET semiconductor fabrication and backside wet etching. The PSAFET located at the front side measured pressure change using 300 nm thin-nitride membrane when a membrane was slightly strained by the small deflection of membrane shape from backside with any physical force. The PSAFET showed high sensitivity around threshold voltage, because threshold voltage variation was composed of fractional function form in sensitivity equation of current variation. When gate voltage was biased close to threshold voltage, a fractional function form had infinite value at $V_{tn}$, which increased the current variation of sensitivity. Threshold voltage effect was dominant right after the PSAFET was turned on. Narrow transistor channel established by small current flow was choked because electron could barely cross drain-source electrodes. When gate voltage was far from threshold voltage, threshold voltage effect converged to zero in fractional form of threshold voltage variations and drain current change was mostly determined by mobility changes. As the PSAFET fabrication was compatible with a polysilicon FET in CMOS fabrication, it could be adapted in low pressure sensor and bio molecular sensor.