• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.423-426
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• 2006

Distance relays achieve selective tripping by measurement of all short circuit fault conditions inside set reaches. The direction of the fault, forward or reverse is commonly determined with a dedicated measurement to ensure selectivity under all conditions. For the direction decision (measurement) a number of alternatives are available. This paper describes a loop selective direction measurement and illustrates by means of a typical fault why this is superior to a non loop selective direction measurement such as that based on negative sequence quantities.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.2
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• pp.32-45
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• 2000

This paper presents the analytic derivation of the SINR, when a linear array antenna is accommodated into the cellular CDMA basestation receiver, in relation to the two major performance effecting factors in beamforming(BF) applications, i. e., the direction selectivity, which refers to the narrowness of the mainbeam width, and the direction-of-arrival(DOA) estimation accuracy. The analytically derived results are compared with the operation simulation of the receiver realized with the several BF algorithms and their agreements are confirmed, consequently verifying the correctness of the analysis and the operation simulation. In order to investigate separately the effects of the errors occurring in the direction estimation and in the interference suppression, which are the two major functional components of general BF algorithms, both the algorithms of steering BF and the minimum- variance- distortionless-response(MVDR) BF are applied to the analysis. A signal model to reflect the spatially scattering phenomenon of the RF waves entering into the .:nay antenna, which directly affects on the accuracy of the BF algorithm's direction estimation, is also suggested in this paper and applied to the analysis and the operation simulation. It is confirmed from the results that the enhancement of the direction selectivity of the away antenna is not desirable in view of both the implementation economy and the BF algorithm's robustness to the erroneous factors. Such a trade-off characteristics is significant in the sense that it can be capitalized to obtain an economic means of BF implementation that does not severely deteriorate its performance while ensuring the robustness to the erroneous effects, consequently manifesting the significance of the analysis results of this paper that can be used as a design reference in developing BF algorithms to the cellular CDMA system.

• Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.177-181
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• 2005

Fishing selectivity is determined by the level of voluntary escaping behavior in accordance with decision-making based on the relationship between fish size and mesh size. This study examined movement during the swimming behavior of black porgy in a trawl's towing cod-end and analyzed the movement components such as swimming speed, angular velocity of turning, and distance to the net over time. Most of the observed fish exhibited an optomotor response, maintaining position and swimming speed without changing direction. Others exhibited erratic or 'panic' behavior with sudden changes in swimming speed and direction. The latter behavior involved very irregular and aperiodic variations in swimming speed and angular velocity, termed 'chaotic behavior.' Thus, the results of this study can be applied to a chaotic behavior model as a time series of swimming movements in the towing cod-end for the fishing selectivity.

• Journal of information and communication convergence engineering
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• v.2 no.1
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• pp.22-25
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• 2004

A highly sensitive ammonia gas sensor using thick-film technology has been fabricated and examined. The sensing material of the gas sensor is FeOx-$WO_{3}-SnO_{2}$ oxide semiconductor. The sensor exhibits resistance increase upon exposure to low concentration of ammonia gas. The resistance of the sensor is decreased, on the other hand, for exposure to reducing gases such as ethyl alcohol, methane, propane and carbon monoxide. A novel method for detecting ammonia gas quite selectively utilizing a sensor array consisting of an ammonia gas sensor and a compensation element has been proposed and developed. The compensation element is a Pt-doped $WO_{3}-SnO_{2}$gas sensor which shows opposite direction of resistance change in comparison with the ammonia gas sensor upon exposure to ammonia gas. Excellent selectivity has been achieved using the sensor array having two sensing elements.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.533-540
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• 2013

Purpose: To investigate the synaptic pattern of NMDA glutamate receptor subtype NMDA R1 on the dendritic arbors of ON-OFF direction-selective retinal ganglion cells (DS-RGSs) in developing [(5,10) days postnatal (PN)] mouse retina. Methods: ON-OFF DS-RGCs were injected with Lucifer yellow and the cells were identified by their characteristic morphology. To identify glutamatergic excitatory input from bipolar cell, we used a marker for the membrane traffic motor protein kinesin. Results: We identified DS-RGCs in P5, and P10 mouse retina. The immunofluorescence labeling of NMDA R1 was most prominent in the IPL. Our results showed that their presence upon the entire dendritic arbor of ON-OFF DS-RGCs is without any evidence of asymmetry, which would predict direction selectivity. Conclusions: The glutamatergic input from bipolar cell reveals symmetry pattern in all periods of P5, and P10. The results may suggest that direction selectivity not lies in the specific pattern of NMDA R1 receptors.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.131-143
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• 2012

This paper introduces the double-density discrete wavelet transform using 3 direction separable processing method, which is a discrete wavelet transform that combines the double-density discrete wavelet transform and quincunx sampling method, each of which has its own characteristics and advantages. The double-density discrete wavelet transform is nearly shift-invariant. But there is room for improvement because not all of the wavelets are directional. That is, although the double-density DWT utilizes more wavelets, some lack a dominant spatial orientation, which prevents them from being able to isolate those directions. The dual-tree discrete wavelet transform has a more computationally efficient approach to shift invariance. Also, the dual-tree discrete wavelet transform gives much better directional selectivity when filtering multidimensional signals. But this transformation has more cost complexity Because it needs eight digital filters. Therefor, we need to hybrid transform which has the more directional selection and the lower cost complexity. A solution to this problem is a the double-density discrete wavelet transform using 3 direction separable processing method. The proposed wavelet transformation services good performance in image and video processing fields.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3218-3222
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• 2013

The aminolyses, anilinolysis and pyridinolysis, of bis(2-oxo-3-oxazolidinyl) phosphinic chloride (1) have been kinetically investigated in acetonitrile at 55.0 and $35.0^{\circ}C$, respectively. For the reactions of 1 with substituted anilines and deuterated anilines, a concerted SN2 mechanism is proposed based on the selectivity parameters and activation parameters. The deuterium kinetic isotope effects ($k_H/k_D$) invariably increase from secondary inverse to primary normal as the aniline becomes more basic, rationalized by the transition state variation from a backside to a frontside attack. For the pyridinolysis of 1, the authors propose a stepwise mechanism with a rate-limiting step change from bond breaking for more basic pyridines to bond formation for less basic pyridines based on the selectivity parameters and activation parameters. Biphasic concave upward free energy relationship with X is ascribed to a change in the attacking direction of the nucleophile from a frontside attack with more basic pyridines to a backside attack with less basic pyridines.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.9
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• pp.128-138
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• 1994

In 1.55.mu.m DFB lasers with two non-AR mirrors, I have analyzed the effect of the sturctures of indes and/or gain gratings and mirror positions on the threshold gains, the lasing frequencies, and the beam profiles in longitudinal direction of lasers. I have obtained the optimum condition of static characteristics that ${\Delta}{\Omega}$(the phase difference betweeen index grating and gain grating is 3${\pi}$/4, $({\kappa}L)_{i}$=4~6 in case of $({\kappa}L)_{i}$=0.9 and $({\kappa}L)_{i}$=3~5 in case of $({\kappa}L)_{i}$=0.7. The modal selectivity and intensity uniformity of this optimum condition are 2~2.5 times better than those of the gain-coupled DFB lasers ${\Delta}{\Omega}$=0). The gain-coupled DFB lasers${\Delta}{\Omega}$=0) have 10$^{10) times better modal selectivity and intensity uniformity than the loss-coupled DFB lasers(TEX>${\Delta}{\Omega}$=${\pi}$).

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.119-131
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• 2011

In this paper, we explore the application of 2-D dual-tree discrete wavelet transform (DDWT), which is a directional and redundant transform, for image coding. DDWT main property is a more computationally efficient approach to shift invariance. Also, the DDWT gives much better directional selectivity when filtering multidimensional signals. The dual-tree DWT of a signal is implemented using two critically-sampled DWTs in parallel on the same data. The transform is 2-times expansive because for an N-point signal it gives 2N DWT coefficients. If the filters are designed is a specific way, then the sub-band signals of the upper DWT can be interpreted as the real part of a complex wavelet transform, and sub-band signals of the lower DWT can be interpreted as the imaginary part. The quincunx lattice is a sampling method in image processing. It treats the different directions more homogeneously than the separable two dimensional schemes. Quincunx lattice yields a non separable 2D-wavelet transform, which is also symmetric in both horizontal and vertical direction. And non-separable wavelet transformation can generate sub-images of multiple degrees rotated versions. Therefore, non-separable image processing using DDWT services good performance.

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1021-1026
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• 1997

RuO2 thin film has reasonably good conductivity and stiffness and it is thought to substitute for the cantilever beam made up of Pt and Si3N4 double layers in microactuators. Therefore, anisotopic Si etching was performed using RuO2 thin film as a mask layer in 25 wt. % TMAH water solution. In the etching temperature ranging from 6$0^{\circ}C$ to 75$^{\circ}C$, the etch rates of all the crystallographic directions increased linearly as the etching temperature increased. The etch rate ratio(selectivity) of [111]/[100] which varied from 0.08 to 0.14, was not sensitive to temperature. The activation energies for [110] direction, [100] direction and [111] direction were 0.50, 0.66 and 1.04eV, respectively. RuO2 cantilever beam with a clean surface was formed at the etching temperatures of 6$0^{\circ}C$ and $65^{\circ}C$. But the damages due to formation of pin holes on RuO2 surface were observed beyond 7$0^{\circ}C$. The tensile stress of RuO2 thin films caused the cantilever bending upward. As a result, it was demonstrated that the formation of conducting oxide RuO2 cantilever beam which can replace the role of an electrode and supporting layer could be possible by TMAH solution.