• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.10
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• pp.3304-3312
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• 1996

An experimental study on the convective heat transfer characteristics was performed for a two-dimensional wall attaching offset jet(WAOJ). Thermochromic liquid crystal was used to measure the plate wall temperature. The Nusselt number was measured for Reynolds numbers from 6, 500 to 39, 000, and the offset ratios from 0.5 to 15. The maximum Nusselt number point coincides with the time-averaged reattachment point and Nusselt number decreases monotonically after the jet reattaches on the wall. In the recirculation region Nusselt number minimize near the upstream corner and then increases as X/D decreases to vanishes. This suggests the existence of secondary vortices, causing an additional mixing of the flow in the corner. The correlations between the local Nusselt number and Reynolds number, Re, offset ratio, H/D, and streamwise distance, X/D are presented.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.58-68
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• 1999

This study was carried out to verify the distribution patterns of Salix gracilistyla and Phragmites japonica communities known as obligatory riparian species according to physical factors such as micro-landforms, substrates, etc., at Soo-ip stream corridor. Firstly four vegetation types - Salix gracilistyla dominant type, Phragmites japonica dominant type, mixed type of two species, and mixed type of two species to other species, were classified by cluster analysis based on UPGMA-Euclidean distance. Also these vegetation types showed many different distribution patterns in response to the longitudinal and lateral view along the stream corridor and substrate composition. Salix gracilistyla was major component of dominant vegetation types developed at attack point of bending reach and on substrates composed of rock fragments, but contrastly Phragmites japonica was most important component of dominant vegetation types at point bar of bending reach and floodplain, and on substrates composed of soil materials. Secondly the species and environment biplot form CCA strongly supported the vegetation types divided by classification. Namely Salix gracilistyla was closely correlated with rock fragments and steep slope, which is resistant to physical action even though located near running water. But Phragmites japonica showed a high correlation with soil particles sedimented at floodplain by divergent flow.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.240-246
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• 2006

This paper performed to investigate on vertical temperature distribution, effective draft temperature (ETD) and PMV (Predicted Mean Vote) in the classroom, which is located YangSan city (Kyungsangnam-Do), Korea, is equipped with ceiling unit. The vertical temperature difference between F.L+10 cm (ankle) and F.L+120 cm (neck) of a measuring point which is adjacent corridor in the classroom showed about $1^{\circ}C$ but of measuring point which is adjacent outdoor expressed up to $4^{\circ}C$, The effective draft temperature (ETD) is -2.3 and -0.52 and 0.67 at near ceiling unit but is 1.2 and 3.3 at far from ceiling unit. The PMV of total classroom showed the range of 'Cold' and 'Slightly Cold.' Therefore, to achieve comfort condition in the classroom is equipped with ceiling unit, the location of ceiling unit and discharge angle and discharge distance from ceiling unit are very important elements.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.447-449
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• 2021

Various wireless sensor network protocols have been proposed to maintain the network for a long time by minimizing energy consumption. Using the K-means clustering algorithm takes longer to cluster than traditional hierarchical algorithms because the center point must be moved repeatedly until the final cluster is established. For K-means clustering-based protocols, only the residual energy of nodes or nodes near the center point of the cluster is considered when the cluster head is elected. In this paper, we propose a new wireless sensor network protocol based on K-means clustering to improve the energy efficiency while improving the aforementioned problems.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.spc1
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• pp.90-96
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• 2024

In this paper, we propose a technique to model high resolution seafloor topography with 1m intervals using actual water depth data near the east coast of the Korea with 1.6km distance intervals. Using a feature point extraction algorithm that harris corner based on deep learning, the location of the center of seafloor mountain was calculated and the surrounding topology was modeled. The modeled high-resolution seafloor topography based on deep learning was verified within 1.1m mean error between the actual warder dept data. And average error that result of calculating based on deep learning was reduced by 54.4% compared to the case that deep learning was not applied. The proposed algorithm is expected to generate high resolution underwater topology for the entire Korean peninsula and be used to establish a path plan for autonomous navigation of underwater vehicle.

• The Journal of Korean Medicine
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• v.42 no.4
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• pp.102-119
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• 2021

Objectives: Facial diagnosis is an important part of clinical diagnosis in traditional East Asian Medicine. In this paper, using a fully automated facial shape analysis system, we show that facial morphological features are associated with cold pattern. Methods: The facial morphological features calculated from 68 facial landmarks included the angles, areas, and distances between the landmark points of each part of the face. Cold pattern severity was determined using a questionnaire and the cold pattern scores (CPS) were used for analysis. The association between facial features and CPS was calculated using Pearson's correlation coefficient and partial correlation coefficients. Results: The upper chin width and the lower chin width were negatively associated with CPS. The distance from the center point to the middle jaw and the distance from the center point to the lower jaw were negatively associated with CPS. The angle of the face outline near the ear and the angle of the chin line were positively associated with CPS. The area of the upper part of the face and the area of the face except the sensory organs were negatively associated with CPS. The number of facial morphological features that exhibited a statistically significant correlation with CPS was 37 (unadjusted). Conclusions: In this study of a Korean population, subjects with a high CPS had a more pointed chin, longer face, more angular jaw, higher eyes, and more upward corners of the mouth, and their facial sensory organs were relatively widespread.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.11
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• pp.36-45
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• 1992

A numerical trajectory planning method for path-constrained trajectory planning is proposed which ensures collision-free and time-optimal motions for two robotic manipulators with limited actuator torques and velocities. For each robot, physical constraints of the robots such as limited torques or limited rotational velocities of the actuators are converted to the constraints on velocity and acceleration along the path, which is described by a scalar variable denoting the traveled distance from starting point. Collision region is determined on the coordination space according to the kinematic structures and the geometry of the paths of the robots. An Extended Coordination Space is then constructed` an element of the space determines the postures and the velocities of the robots, and all the constraints described before are transformed to some constraints on the behaviour of the coordination-velocity curves in the space. A dynamic programming technique is them provided with on the discretized Extended Coordination Space to derive a collision-free and time-optimal trajectory pair. Numerical example is included.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.519-525
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• 2000

The effect of nozzle diameter on the local Nusselt number distributions has been investigated for an axisymmetric turbulent jet impinging on the flat plate surface. The flow at the nozzle exit has a fully developed velocity profile. A uniform heat flux boundary condition at the plate surface was created using gold film Intrex. Liquid Crystal was used to measure the plate surface temperature. The experiments were made for the jet Reynolds number (Re) 23,000, the dimensionless nozzle to surface distance (L/d) from 2 to 14, and the nozzle diameter (d) from 1.36 to 3.40 cm. The results show that the Nusselt number at and near the stagnation point increase with an increasing value of the nozzle diameter.

• Wind and Structures
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• v.19 no.5
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• pp.541-563
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• 2014

This paper investigates the topographic effects on wind characteristics over hilly terrain, based on wind data recorded at a number of meteorological stations in or near complex terrain. The multiply data sources allow a more detailed investigation of the flow field than is normally possible. Vertical profiles of mean and turbulent wind components from a Sodar profiler were presented and then modeled as functions of height and wind speed. The correlations between longitudinal and vertical wind components were discussed. The phenomena of flow separation and generation of vortices were observed. The distance-dependence of the topographic effects on gust factors was revealed subsequently. Furthermore, the canyon effect was identified and discussed based on the observations of wind at a saddle point between two mountain peaks. This study aims to further understanding of the characteristics of surface wind over rugged terrain. The presented results are expected to be useful for structural design, prevention of pollutant dispersion, and validation of CFD (computational fluid dynamics) models or techniques over complex terrains.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.6
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• pp.836-842
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• 1990

The noise currents in the load of cascaded transmission lines excited by a nearly small loop are analyzed and the effective approxiamte method by which we can calculate these currents easily and the computation time can be significantly reduced is developed. Numerical results for n=3 are well agreed with those of Smith by the maximum difference of 3-4dB and show that the length of a segment of line regarded to be illuminated by uniform electric fields should be 1.3 times the distance from the loop to the point midway between the conductors.