• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.11
• /
• pp.955-966
• /
• 2013

We propose two feedback interference cancellers(FICs) to improve the performance of the equalization digital on-channel repeater(EDOCR) with the FIC for the ATSC DTV broadcasting system. The FIC estimates the feedback channel between Tx. and Rx. antennas of the repeater by cross-correlating the reference signal and the feedback signal. Since there is a DC pilot which ruins the white property of the ATSC DTV signals, the FIC cannot estimate the feedback channel accurately. To solve the problem, the structural method which uses an additional DC pilot free reference for feedback channel estimation and the algorithmic method based on the digital signal processing which whitens the ATSC DTV signals and performs the feedback cancellation in the whitened signal domain. Simulation results show that the proposed two FICs show better feedback cancellation performance than the conventional FIC.

• Bulletin of the Korean Chemical Society
• /
• v.10 no.2
• /
• pp.196-200
• /
• 1989

Some s-triazine herbicides, namely simazine, atrazine, and propazine present as trace components in a complex mixture were analyzed by GC/MS and GC/MS/MS methods. Even though monitoring the molecular ions was the best in terms of sensitivity, adequate analysis could not be done when interfering species were present. When doubly charged ions which appeared at characteristic m/z values were monitored, chromatograms were rather free from interference. More importantly, selected reaction monitoring was found to provide a selective means of detection with general applicability.

• International Journal of Control, Automation, and Systems
• /
• v.2 no.1
• /
• pp.107-117
• /
• 2004

A new algorithm for planning a collision-free path based on an algebraic curve as well as the concept of path space is developed. Robot path planning has so far been concerned with generating a single collision-free path connecting two specified points in a given robot workspace with appropriate constraints. In this paper, a novel concept of path space (PS) is introduced. A PS is a set of points that represent a connection between two points in Euclidean metric space. A geometry mapping (GM) for the systematic construction of path space is also developed. A GM based on the 2$^{nd}$ order base curve, specifically Bezier curve of order two is investigated for the construction of PS and for collision-free path planning. The Bezier curve of order two consists of three vertices that are the start, S, the goal, G, and the middle vertex. The middle vertex is used to control the shape of the curve, and the origin of the local coordinate (p, $\theta$) is set at the centre of S and G. The extreme locus of the base curve should cover the entire area of actual workspace (AWS). The area defined by the extreme locus of the path is defined as quadratic workspace (QWS). The interference of the path with obstacles creates images in the PS. The clear areas of the PS that are not mapped by obstacle images identify collision-free paths. Hence, the PS approach converts path planning in Euclidean space into a point selection problem in path space. This also makes it possible to impose additional constraints such as determining the shortest path or the safest path in the search of the collision-free path. The QWS GM algorithm is implemented on various computer systems. Simulations are carried out to measure performance of the algorithm and show the execution time in the range of 0.0008 ~ 0.0014 sec.

• Korean Journal of Environmental Biology
• /
• v.37 no.3
• /
• pp.396-405
• /
• 2019

A new species of free-living marine nematode is described from intertidal sediments of the East Sea, Korea. Phanoderma koreense sp. nov. is characterized by the presence of well-developed pharyngeal and cephalic capsule, six inner labial sensilla present as minute papillae around with circular groove, long and slender spicules with 4-5 serrated distal end, located at the base of the precloacal supplement, a series of eight to nine stout and short setae on the ventral cloacal region and conico-cylindrical tail with two pairs of blunt setae. In this study, we provide taxonomic descriptions and illustrations of a new species by differential interference contrast microscope and a pictorial key to the valid species of Phanoderma Bastian, 1865. This is the first record of the genus Phanoderma in the East Sea, Korea.

• Korean Journal of Optics and Photonics
• /
• v.9 no.3
• /
• pp.151-155
• /
• 1998

A new Fabry-Perot tunable filter has been built with simple construction, which does not require any additional aligning and/or beam-confining components for the reduction of the diffraction loss. For this feature, one of the two fibers for the filter is processed to have a concave mirror whose curvature is the same as that of the wavefront of the Gaussian beam from the first fiber. After high reflection coatings, the two fibers are aligned to result in an FP filter whose bandwidth, free spectral range, and insertion loss is 1.47nm, 52nm, 5.6dB respectively.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1128-1131
• /
• 1996

The collision-free path planning presented here uses linear parametric curve with one intermediate connection point between start and target points. The algorithm, in which connection point is organized in elliptic chord.(.theta., .delta.), maps objects in Euclidean Space into images in CPS through intersection check between path and obstacles a process defined as GM. Elliptic locus has special property that the total distance between focus points through a point on ellipse is the same regardless of .theta.. Hence by locating the start and target points to focus points of ellipse, and organizing connection point in elliptic coordinate, the .delta.-axis of CPS represents length of path. The GM of EWS requires calculation of interference in circumferential direction only. The procedures for GM is developed which include categorization of obstacles to reduce calculation amount. Simulations of GM of EWS, on a PC with Pentium/90MHz, is carried out to measure performance of algorithm and the results are reported on a table. The simulations are done for number of cases with different number of obstacles and location of start/target points.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1996.10a
• /
• pp.159-167
• /
• 1996

This paper describes the theory and verification of a method which utilizes the free decay response of a structure to determine its vibration parameters. The theory of the method is base on the formulation of a system matrix, contains information characterizing the complete set of modal parameters of the system, and its eigen-solution problem. The applicability of the method is verified by simulated free decay response data of a cantilever bean The method described was used to determined the parameters related to the first five generated modes of vibration of a cantilever beam. It involves two very close natural frequencies which could not be identified using a frequency sweep test(peak amplitude) because of interference between modes.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.852-855
• /
• 2002

This paper presents a design of FIR near-equiripple Nyquist filters having zero-intersymbol interference (ISI) and low sensitivity to timing jitter, with coefficients taking only discrete values. Using an affine scaling linear programming algorithm, an optimum discrete coefficient set can be obtained in a feasible computational time. Also presented is a pipelined multiplier-free FIR filter realization with periodically time-varying (PTV) coefficients based on a hybrid form suitable for Nyquist filter. The realization exploits the coefficient symmetry to reduce the hardware by about one half. High speed computation and low power consumption are achieved by its pipelined and low fan-out structure.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.9B
• /
• pp.1226-1235
• /
• 2001

The convergence analysis of the improved multiplication free adaptive digital filter (IMADF) with a fractionally-spaced equalizer (FSE) to remove the intersymbol interference (ISI) in fast data transmission is presented. The IMADF structure use the one-step predicted filter in the multiplication-free adaptive digital filter (MADF) structure using the DPCM and Sign algorithm. In the experimental results, the IMADF algorithm has reduced the computational complexity by use of only the addition operation without a multiplier. Also, under the condition of identical stationary-state error, it could obtain the stabled convergence characteristic that the IMADF algorithm is almost same as the sign algorithm, but is better than the MADF algorithm. Here, this algorithm has effective characteristics when the correlation of the input signal is highly.

• Animal cells and systems
• /
• v.10 no.4
• /
• pp.219-225
• /
• 2006

As a result of the faunistic survey of the free-living marine nematodes from coastal algal beds and sublittoral sands in South Korea, we report a meiobenthic species, Desmoscolex cosmopolites Timm, 1970, for the first time from the western Pacific as well as Korean waters. Among 17-ring Desmoscolex species, D. cosmopolites is represented by the following combination of characters: absence of subventral setae on 10th and 14th main rings and the presence of subdorsal setae with large angular lance-shaped tip. A detailed morphological redescription is provided using a scanning electron microscope and a differential interference contrast microscope. Character comparison between D. cosmopolites and its allied congeneric species is also analysed.