• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2006.05a
• /
• pp.496-499
• /
• 2006

The solar cells should be operated at the maximum power point because its output characteristics are greatly fluctuate on the variations of insolation, temperature and loads. To obtain maximum power from solar cell, photovoltaic system cell power system usually requires maximum power point tracking controller. This paper propose Maximum power point tracking method using zero slope of differential value of maximum power. The power compare method traces to maximum power point rapidly but oscillate on the maximum power point largely, when quantity insolation variation is big. The power compare method is traces to maximum power point slowly but oscillate maximum point on the maximum power point smally, when quantity insolation variation is small. To solve two problem of the power compare method, designed zero slope of differential value of maximum power.

• Journal of KIISE:Computer Systems and Theory
• /
• v.32 no.8
• /
• pp.411-417
• /
• 2005

We present a method to reconstruct a canal surface from a point cloud (a set of unorganized points). A canal surface is defined as a swept surface of a moving sphere with varying radii. By using the shrinking and moving least-squares methods, we reduce a point cloud to a thin curve-like point set which can be approximated to the spine curve of a canal surface. The distance between a point in the thin point cloud and a corresponding point in the original point set represents the radius of the canal surface.

• Journal of Korean Society of Forest Science
• /
• v.112 no.2
• /
• pp.195-208
• /
• 2023

This study aimed to use three-dimensional point cloud data (PCD) obtained from Terrestrial Laser Scanning (TLS) and Mobile Laser Scanning (MLS) to evaluate a deep learning-based species classification model for two tree species: Pinus koraiensis and Larix kaempferi. Sixteen models were constructed based on the three conditions: LiDAR platform (TLS and MLS), down-sampling intensity (1024, 2048, 4096, 8192), and deep learning model (PointNet, PointNet++). According to the classification accuracy evaluation, the highest kappa coefficients were 93.7% for TLS and 96.9% for MLS when applied to PCD data from the PointNet++ model, with down-sampling intensities of 8192 and 2048, respectively. Furthermore, PointNet++ was consistently more accurate than PointNet in all scenarios sharing the same platform and down-sampling intensity. Misclassification occurred among individuals of different species with structurally similar characteristics, among individual trees that exhibited eccentric growth due to their location on slopes or around trails, and among some individual trees in which the crown was vertically divided during tree segmentation.

• Tunnel and Underground Space
• /
• v.19 no.6
• /
• pp.473-478
• /
• 2009

The accuracy of point load apparatus is depend on point to point coaxial fitting. Also, the estimation of applied point load using the pressure gauge frequently lead to erroneous results. An improved point load apparatus has been developed in this study by mounting linear bearing on polished support rod, and eccentric error of point to point axis has been sustained less than 0.1 mm even under series of extreme work load conditions. Two digital displacement gauges are attached to measure the distance from point to point with sample specimen. A load cell mounted at the end of upper conical platen measure the applied net load on sample instead of preassure gauge. Total of 107 point load tests has been achieved to assure the quality and performance of developed apparatus. This exercise turned out to be successful.

• Journal of Educational Research in Mathematics
• /
• v.26 no.4
• /
• pp.731-754
• /
• 2016

The purpose of the study is to identify the point of knowing. The point of knowing is the time, which indicates that 'knowing' occurs in the recognition process. To understand recognition process, the researchers analyzed the questions in units of lessons presented in elementary mathematics textbooks. The researchers analyzed the validity of the point of knowing and found out the basis of the point of knowing. The results are as follows. First, the point of knowing is time to expect to change from a leaner's 'not-knowing' to 'knowing'. Second, the point of knowing can be identified with the questions on textbooks to ask students to do practical action. Third, the point of knowing is closely related to instructional objective in a class. Fourth, in relation to subsidiary awareness and focal awareness, the point of knowing corresponds to focal awareness. Fifth, the point of knowing is equivalent to the inflection point at which personalization/contextualization is changed into depersonalization/decontextualization.

• Journal of Environmental Science International
• /
• v.13 no.6
• /
• pp.497-503
• /
• 2004

In this research, we have performed a T-test to see how the relationship between dependent variable or visual point level and independent variable or visual quantity is in order to clear up the correlation between pattern of visual point and visual quantity by the constituents of a view from a different visual point level and the results are as follows: 1) In case of the character of Mt. Uam landscape of the city, Uamsan is set as a fixed point and about a direction of view(D), the north is a datum point from which the range of direction is distributed within 1800 westwardly and the visual range(R) is also within 2000m. An elevation is an average of 7.40 and the average story of the buildings is 3.85. Here the height of a story is about 4m so the average of the visual point difference is estimated at 15.4m. 2) The type of visual point is divided into the intersection group and the front of the highly used public buildings group. Double intersection types account for about 78.80%(52 spots) which forms a majority part of LCP. 3) The analysis of the difference of visual point level divided by eye level and that of the top of the buildings has been proved that there's a sharp difference resulted from t-test at 1 % significant level. The significant difference of elevation from height difference(l5.93m), however, has not been shown. 4) From the result of T-test about visual quantity by the elements of a view from a different visual point level, the visual quantity of mountain(VQM), sky(VQS), ground(VQG) is significant at about 1% each and that of building(VQB) is at about 5%. The difference in visual quantity of a mountain by the visual point level is at about 4% which can meet a marginal level of LCP necessary for evaluation of mountainscape.

• Journal of Acupuncture Research
• /
• v.24 no.4
• /
• pp.25-33
• /
• 2007

Objective : The purpose of this study is to compare the effects of near acupuncture point needling and remote acupuncture point needling on treating ankle sprain of acute stage. Methods : From March 1st, 2007 to May 30th, 2007, the 50 patients who had visited Iksan oriental medical hospital, Wonkwang university with acute ankle sprain were divided into 2 groups ; one group took near acupunture point needling, and the other group took remote acupunture point needling. Both group had been treated with the same additional rest, ice, compression and elevation(RICE) therapy. To evaluating the efficiency of each treatment, Visual Analog Scale(VAS) and Ankle-Hindfoot Scale(AHS) were applied before 1st treatment and after 3rd treatment. Results : As a result of evaluation by using AHS, the score change comparison between the two groups had no significance after the treatment. As a result of evaluation by using VAS, treatment score of remote acupucture point needling was marked lower than score of near acupucture point needling. Conclusion : Remote acupucture point needling is more effective than near acupucture point needling in controlling the pain of acute ankle sprain.

• Spatial Information Research
• /
• v.6 no.1
• /
• pp.11-23
• /
• 1998

Map generalization functions to visualize the spatial data or to change their scale by changing the level of details of data. Until recently, the studies on map generalization have concentrated more on line features than on point features. However, point features are one of the essential components of digital maps and cannnot be ignored because of the great amount of information they carry. This study, therefore, aimed to find out a detailed procedure of point features' generalization. Particularly, this work chose the distribution pattern of point features as the most important factor in the point generalization in investigating the geometric characteristics of source data. First, it attempted to find out the characteristics of distribution pattern of point features through quadrat analysis with Grieg-Smith method and nearest-neighbour analysis. It then generalized point features through the generalization threshold which did not alter the characteristics of distribution pattern and the removal of redudant point feautres. Therefore, the generalization procedure of point features provided by this work maintained the geometric characteristics as much as possible.

• Journal of IKEEE
• /
• v.17 no.3
• /
• pp.346-351
• /
• 2013

Low-cost and low-power are important requirements in mobile systems. Thus, when a floating-point arithmetic unit is needed, 24-bit floating-point format can be more useful than 32-bit floating-point format. However, a 24-bit floating-point arithmetic unit can be risky because it usually has lower accuracy than a 32-bit floating-point arithmetic unit. Consecutive floating-point operations are performed in 3D graphic processors. In this case, the verification of the floating-point operation accuracy is important. Among 3D graphic arithmetic operations, the floating-point division is one of the most difficult operations to satisfy the accuracy of $10^{-5}$ which is the required accuracy in OpenGL ES 3.0. No 24-bit floating-point divider, whose accuracy is algebraically verified, has been reported. In this paper, a 24-bit floating-point divider is analyzed and it is algebraically verified that its accuracy satisfies the OpenGL requirement.

• The Journal of Korean Medicine
• /
• v.15 no.2 s.28
• /
• pp.241-252
• /
• 1994

It is known that the pattern of combustion temperature can be classified into preheating, heating. retaining and cooling periods. In this experiment. the authors have studied the heating mechanism by the density of moxa material during the heating and retaining periods. The starting point. the point at which it begins to reach the maximum gradient temperature. the ending point of the heating period. and the ending point of the retaining period were measured in order to get effective stmulation by repetition of moxa-combustion. For the experiment. samples of 300mg. 400mg, and 500mg of moxa material were molded into conical molds with each 10mm in diameter and height resulting in the volume of $0.26cm^3$. The following results were obtained: The $300mg/0.26cm^3$ denstiy sample reached al1 points tested faster than the samples of $400mg/0.26cm^3$ and $500mg/0.26cm^3$ It dose not reveal any statistical differences between $400mg/0.26cm^3$ and $500mg/0.26cm^3$ in the ending point. the point at which it begins to reach the maximum gradient temperature of the heating period or the ending point of the reataining period The only difference shown was in the starting point of the heating period. According to the above results. it is concluded that the lower density moxa material reached each point of the the respective period faster than the high density moxa material.