A novel one-body dual laser profile based vibration compensation in 3D scanning

Lim, Yongseok,Choi, Woong,Park, Yongju,Oh, Sangwook,Kim, Younghun,Park, Jongsun Elsevier 2018 MEASUREMENT -LONDON- Vol.130 No.-

<P><B>Abstract</B></P> <P>Recently, the 3D laser profile scanner has often been used for the precise measurement of 3D surface information (object surface) such as height, area, and slope. However, a difficulty encountered with the conventional laser scanning method is that it cannot compensate for the errors resulting from vibration, so the scanned object should be measured in a fixed (immobile) state. In this paper, we propose a novel dual laser profile method and its error compensation algorithm to compensate for vertical vibration, even with a moving object. In order to remove errors caused by vibration, the proposed system projects two laser profiles onto the surface, such that the projected position overlaps the one with the previous position. With the overlapped position, the height difference between the measured objects is used to calculate the vibration errors. To generate two laser profiles simultaneously, we present a novel approach for generating two laser profiles from one laser-emitting source (a one-body dual line laser using a triangular structured blazed grating reflector). By exploiting the one-body dual line laser and error compensation algorithm, the proposed 3D laser profile scanner system achieves an error reduction of about 96.3% in the root mean square error (RMSE), compared to the conventional approach.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Overlapping two laser profiles with time difference allows vibration compensation. </LI> <LI> One laser source generates two precise laser profiles using grating structure. </LI> <LI> Global compensation algorithm corrects error from superimposing two laser profiles. </LI> </UL> </P>

An Adaptive Impedance-Matching Network Based on a Novel Capacitor Matrix for Wireless Power Transfer

Yongseok Lim,Hoyoung Tang,Seungok Lim,Jongsun Park Institute of Electrical and Electronics Engineers 2014 IEEE transactions on power electronics Vol. No.

<P>In a wireless power transfer (WPT) system via the magnetic resonant coupling, one of the most challenging design issues is to maintain a reasonable level of power transfer efficiency (PTE), even when the distance between the transmitter and the receiver changes. When the distance varies, the PTE drastically decreases due to the impedance mismatch between the resonator of the transmitter and that of the receiver. This paper presents a novel serial/parallel capacitor matrix in the transmitter, where the impedance can be automatically reconfigured to track the optimum impedance-matching point in the case of varying distances. The dynamic WPT matching system is enabled by changing the combination of serial and parallel capacitors in the capacitor matrix. An interesting observation in the proposed capacitor matrix is that the resonant frequency is not shifted, even with capacitor-matrix tuning. In order to quickly find the best capacitor combination that achieves maximum power transfer, a window-prediction-based search algorithm is also presented in this paper. The proposed resonance WPT system is implemented using a resonant frequency of 13.56 MHz, and the experimental results with 1W power transfer show that the transfer efficiency increases up to 88 % when the distance changes from 0 to 1.2 m.</P>

A Novel Phase-Control-Based Energy Beamforming Techniques in Nonradiative Wireless Power Transfer

Yongseok Lim,Jongsun Park Institute of Electrical and Electronics Engineers 2015 IEEE transactions on power electronics Vol. No.

<P>Recent efforts to increase the energy transfer efficiency in magnetic resonant coupling-based wireless power transfer (WPT) systems, have been focused on improving quality factor, precision of impedance matching, and position alignment between the resonators. Although those approaches are effective to increase transfer efficiencies, the transferred energy can easily be wasted due to leakage flux of nondirectional fields. In this paper, we present a novel magnetic field shaping technology for improving the energy efficiency in a near-field WPT system. In this study, the beamforming techniques that have been used for radio frequency systems are efficiently exploited in a WPT system to improve the transfer efficiencies by minimizing unnecessary leakage flux. The optimal antenna structure for energy forming is first determined through mathematical analysis. Using the proposed crossed antennas, the phase-control method is effectively used to form magnetic fields in particular directions. The proposed energy forming-based WPT system using crossed antennas is implemented with the phase control of three-power stack transmitters. The experimental results matches well with the theoretical analysis, and the energy-forming approach for synthesizing the magnetic fields achieves average improvements of the transfer efficiency and transfer distance of up to 20.1% and 30%, respectively, over the conventional nonradiative energy transfer approach at 1 m distance.</P>

Analysis of Antenna Structure for Energy Beamforming in Wireless Power Transfer

Lim, Yongseok,Ahn, Hyun-Seok,Park, Jongsun Institute of Electrical and Electronics Engineers 2017 IEEE transactions on antennas and propagation Vol.65 No.11

<P>The technology to send a magnetic field in a particular direction, known as energy beamforming, has been recently introduced as a magnetic field shaping technology in nonradiative wireless power transmission. In general, one of the most efficient conditions for energy beamforming is that the magnetic fields induced by each antenna should be synthesized to head the same direction. To synthesize the magnetic fields induced at each antenna, interference by mutual inductance that can occur between transmitting (TX) antennas should be minimized. In addition, energy should not be exchanged between the TXs, otherwise it lowers the transmission efficiencies of TX and receiving antenna. In this paper, we present an optimal antenna structure that minimizes the mutual inductance between two TX antennas. First, we have analyzed the mutual inductance between TX antennas that have asymmetric sizes with different antenna lengths and arrangement angles. The directivity of the magnetic field vector is also investigated through an experimental analysis of an antenna structure. Finally, it has been verified that the optimal TX antennas for energy beamforming should be symmetric, which means that all the length of antennas are same and disposed perpendicular to each other. The experimental results show that the deviations of magnetic field directivity for symmetric and asymmetric antennas are 0.045 and 0.355, respectively, which shows that the symmetric structure shows 8.2 times larger consistency over the asymmetric structure.</P>

금강 하구역의 습지식물상

임용석,신현철 순천향대학교 기초과학연구소 2004 순천향자연과학연구 논문집 Vol.10 No.2

The flora of hydrophytes and hygrophytes in Geumgang estuary were investigated at 25 sites from June 2000 to October 2000. The flora was composed of 23 families, 34 genera, and 43 taxa. Among them, the hydrophytes were confimed as 24 taxa and hygrophytes were 19 taxa. Hydrophytes were composed of 14 taxa emergent hydrophytes, 4 taxa submerged hydrophytes, 4 taxa floating leaved hydrophytes, and 2 taxa free floating hydrophytes. Phragmites communis Trin. was confimed as the most frequently distributed taxon, which was distributed at 15 sites, and next, Trapa japonica Flerov and Zizania latifolia Turcz. were distributed at 9 sites.

유압 굴삭기의 전도율 표시장치의 개발

임태형,최종환,김용석,이홍선,양순용 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

This paper deals with tipping over of hydraulic excavator's crane work. If excavator lift too heavy weight, excavator tipped up. This is 38% of whole excavator accidents. In this paper, tipping over load which is maximum load of excavator can lift with displacement of excavator links, real load and tipping over rate are calculated with Zero Moment Point. We designed the tipping-over stability criterion algorithm considering the dynamic characteristics to which ZMP theory is applied and discussed the usefulness of the proposed algorithm compared with the moment equilibrium equation through the simulation and the actual test.

A study of TiO ₂ /carbon black composition as counter electrode materials for dye-sensitized solar cells

Lim, Jeongmin,Ryu, Sang Yeoul,Kim, Jeonghun,Jun, Yongseok Springer 2013 NANOSCALE RESEARCH LETTERS Vol.8 No.1

<P>This study describes a systematic approach of TiO<SUB>2</SUB>/carbon black nanoparticles with respect to the loading amount in order to optimize the catalytic ability of triiodide reduction for dye-sensitized solar cells. In particular, the cell using an optimized TiO<SUB>2</SUB> and carbon black electrode presents an energy conversion efficiency of 7.4% with a 5:1 ratio of a 40-nm TiO<SUB>2</SUB> to carbon black. Based on the electrochemical analysis, the charge-transfer resistance of the carbon counter electrode changed based on the carbon black powder content. Electrochemical impedance spectroscopy and cyclic voltammetry study show lower resistance compared to the Pt counter electrode. The obtained nanostructures and photo electrochemical study were characterized.</P>

현창늪(경상남도 창녕)의 관속식물상

임용석,마선미,나성태,신현철 순천향대학교 기초과학연구소 2004 순천향자연과학연구 논문집 Vol.10 No.2

The flora of vascular plants of wetland in Hyeonchang swamp, Changnyeong, Gyeongsangnam-do were investigated 3 times from 28 June 2001 to 14 September 2001. The flora was composed of 50 families, 93 genera, and 116 taxa. Among them, the hydrophytes were confirmed as 26 taxa(22.4%), hygrophytes were 34 taxa(29.3%), and terrestrial plants were 56 taxa(48.3)/ Hydrophytes were composed of 15 taxa emergent hydrphytes, 5 taxa submerged hydrphytes, 4 taxa floating-leaved hydrophytes, and 3 taxa free-floating hydrophytes. The dominant hydrophytes and hygrophytes were Phragmites communis Trin., Zizania latifolia Turcz., Miscanthus sacchariflorus Benth., and Persicaria maackiana Nakai. The naturalized plants were colledted 6 taxa.

Nuclear energy density functional and the nuclear α decay

Lim, Yeunhwan,Oh, Yongseok American Physical Society 2017 Physical Review C Vol.95 No.3

<P>The nuclear a decay of heavy nuclei is investigated based on the nuclear energy density functional, which leads to the a potential inside the parent nucleus in terms of the proton and neutron density profiles of the daughter nucleus. We use the Skyrme force model, Gogny force model, and relativistic mean-field model to get the nucleon density profiles inside heavy nuclei. Once the nucleon density profiles are determined, the parameters of the nuclear a potential are fitted to the observed a decay half-lives of heavy nuclei. This approach is then applied to predict unknown a decay half-lives of heavy nuclei. To estimate the Q values of unobserved a decays, we make use of the liquid droplet model.</P>

팔당호 연안생태계의 수생식물상과 생태적 특성

임용석,마선미,나성태,최홍근,신현철 한국육수학회 2005 생태와 환경 Vol.38 No.1

팔당호 연안대의 수생식물상과 식생을 파악하기 위하여 2003년 4월부터 2004년 4월까지 9곳의 조사 지점을 선정하여 선방형구법을 이용하여 조사하였다. 팔당호 연안대에는 128종류의 관속식물이 생육하고 있는 것으로 조사되었고, 이중 수생식물은 38종류였다. 수생식물의 경우 정수식물이 21종류로 가장 많았고, 침수식물은 8종류 였고, 침수식물 종류수는 이전 조사보다 감소한 것으로 파악되었다. 팔당호 주요 식생은 애기부들, 줄, 갈대가 우점하는 정수식물대로 파악되었고, 특히 두물머리, 광동교 근처에 넓게 정수식물대가 넓게 발달하였다. 귀화식물은 11종류가 분포하고 있었으나, 출현 빈도는 상대적으로 높았다. 팔당호 연안대에 분포하는 식물의 출현 빈도를 조사 지점을 기준으로 살펴보면, 조사 지점당 수생식물은 2.7종류, 습생식물은 2.5종류, 육지식물은 1.8종류로 파악 되었고, 수직대상분포 식생이 팔당호 연안대에서 발견되었다. 이러한 조사 결과는 팔당호 연안대가 수생태계의 전형적인 특성들을 지니고 있는 것으로 풀이된다. To investigate the flora and vegetation structure of vascular plants in the littoral zone of Paldang Reservoir, from April, 2003 to April 2004, nine sampling sites were selected. Along the Paldang Reservoir, 128 taxa, consisted of 51 families and 96 genera, were identified, among them, hydrophytes were confirmed as 38 taxa, which was comprised 29.7% to total taxa, whereas hygrophytes were 44 taxa and terrestrial plants were 46 taxa. Emergent hydrophytes consists of 21 taxa, including Phragmites australis and Typha angustifolia, and next, submerged hydrophytes were 8 taxa. However, the kinds and vegetation area of submerged hydorphytes were reduced compared to previous studies. In the littoral zone of Paldang Reservoir, the aquatic vegetation was widely developed near Dumulmori, Yangsuri, and Kwangdong Bridge, downstream of Kyungancheon. The average number of hydrophyte per sampling sites were 2.7 taxa, whereas hygrophytes were 2.5, and land plants were 1.8. In addition, the hydrophytes in the littoral zone of Paldang Reservoir showed the typical vertical zonation pattern like a natural swamp. These results mean that the littoral zone of Paldang Reservoir has the typical characteristics of aquatic plant ecosystem.