• Human Ecology Research
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• 제55권5호
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• pp.491-505
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• 2017

This study investigated the development and core mechanism of subitizing in children and adults as well as provides related theoretical and practical discussions. This study was conducted to determine if subitizing changed with the age of participants and if there were differences in subitizing according to the spacing, color, and shape of the stimuli. The subitizing task set (including forty main trials) was prepared. Forty-five children (fifteen each in groups of 3, 4, and 5-year-olds) and fifteen adults were recruited to perform the subitizing tasks. The results demonstrated that the subitizing speed and accuracy of children improved abruptly between age 3 and age 4. Furthermore, there were significant differences in children's subitizing speed according to the spacing and color of the objects. The children's response time decreased when the objects were fully apart or were of diverse colors. In addition, there were partial significant differences in the subitizing speed of children related to the shape of the objects. The subitizing speed of children decreased in a condition (subitizing 5 objects of diverse colors in fixed spacing) when the shapes of the objects were diverse. The subitizing speed of adults only differed according to the space of the objects. The results demonstrate the development of subitizing in early childhood along with the presence of object individuation processing stages underlying subitizing. This study also provides practical information and suggestions for educational curricula that can strengthen the competency of children in systematic and diverse activities.

• 한국초등과학교육학회지:초등과학교육
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• 제33권1호
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• pp.172-180
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• 2014

The first purpose of this study is to distinguish difficult chapters in 'Speed of objects' chapter and find the factors which give difficulty to the teachers and students. Also, it attempts to compare the students' assessment scores with the degree of difficulty in teaching and also with the degree of difficulty in learning. This report is expected to help science teachers develop their PCK(Pedagogical Content Knowledge) for teaching the chapter professionally. 15 teachers who had taught the 'Speed of Objects' chapter and their 386 students took part in the survey to acquire information about the difficulties in teaching and learning. 386 students also received a test to examine their understandings of the chapter. The results of this study are as follow; First, the degree of teachers' and students' difficulty is only affected by the contents, and the degree of onerousness felt by teachers is higher than that of students. Second, The topics caused higher difficulty to teachers were 'Understanding the meaning of motion(2nd lesson)', 'Understanding the meaning and unit of speed(5th lesson)', 'Changing unit of speed(6th lesson)', 'Drawing a distance-time graph(7th lesson)', and 'Understanding the relative motion(10th). The topics that led higher difficulty to students were the contents of 5th, 6th, and 7th lessons. Third, the 'Speed of Objects' chapter can be divided into 4 types of difficulty according to the degree of teaching and learning; 'Strong difficulty', 'Learning difficulty', 'Weak difficulty', and 'Teaching difficulty'. Last, students showed low achievement to the tasks that were related with 'Strong difficulty' and 'Teaching difficulty'.

• 대한인간공학회지
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• 제24권2호
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• pp.51-56
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• 2005

Human perceptional speed is different from its real speed. There is lack of research that the perceptional speed is different from real speed in 2-dimension, because most research of speed perception has concentrated on points and lines. This research investigates the effects of object size on speed perception. In this research, we used 2-D circular objects of the different size, 0.9, 1.8 and $3.6^{\circ}$. The objects moved 9.0, 13.5 and $18.0^{\circ}$ with three different speeds, 6.0, 9.0 and $18.0^{\circ}$/s. Six participants were exposed to the environment with standard scene(size: $1.8^{\circ}$, speed: $9.0^{\circ}$/s and travel distance: $13.5^{\circ}$). After the first scene, another scene in which the object had changed to different sizes, speeds and distances, was shown to the participants. A magnitude estimation method was used to construct a scale of the perceived speed level. The relationship between the perceived and the actual speed level was explained by Stevens's power law that the value was 0.978 with the exponent of 0.992. The size of object had an effect on the speed perception but travel distance was not. The perceptional speed of bigger object was lower than of smaller object. It showed that the degrees of perceptional speed decreased as size of object increased.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2160-2163
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• 2005

Solid freeform fabrication (SFF) technology plays a major role in industry and represents a reasonable percentage of industrial rapid prototyping/tooling/manufacturing (RP/RT/RM) development applications. However, SFF technology still has long way to progress to achieve satisfactory process speed, surface finish and overall quality improvement of its application. Today, three dimensional printing (3DP) technique that is one of SFF technology is receiving many interests, and is applied by various fields. It can fabricate three dimensional objects of solid freeform with high speed and low cost using ink jet printing technology. However, need long curing time after manufacture completion. And it must do post-processing process necessarily to heighten strength of objects because strength of fabricated objects is very weak. Therefore, in this study, we proposed an improved 3DP process that can solve problems of conventional 3DP process. The general 3DP process is method to spout binder simply through printer head on powder, but proposed process is method to cure jetted UV resin by UV lamp after jet UV resin using printhead on powder. The hardening of resin is achieved strongly at early time by UV lamp in proposed method. So, the proposed process can fabricate three dimensional objects with high speed without any post-processing.

• Journal of information and communication convergence engineering
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• 제19권1호
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• pp.61-66
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• 2021

An underwater remotely operated vehicle (ROV) has been implemented. It can inspect foreign substances through a CCD camera while the ROV is running in water. The maximum thrust of the ROV's running thruster is 139.3 N, allowing the ROV to move forward and backward at a running speed of 1.03 m/s underwater. The structural strength of the guard frame was analyzed when the ROV collided with a wall while traveling at a speed of 1.03 m/s underwater, and found to be safe. The maximum running speed of the ROV is 1.08 m/s and the working speed is 0.2 m/s in a 5.8-m deep-water wave pool, which satisfies the target performance. As the ROV traveled underwater at a speed of 0.2 m/s, the inspection camera was able to read characters that were 3 mm in width at a depth of 1.5 m, which meant it could sufficiently identify foreign objects in the water.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2170-2174
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• 2005

Selective Laser Sintering (SLS) is a useful rapid prototyping technique for the manufacture of three dimensional (3D) solid objects directly from a scanning data. A new approach called a Selective Multi-Laser Sintering (SMLS) system has been developed at Korea Institute Machinery & Materials (KIMM) as an industrial type SFFS. This SMLS machine is built with a frame, heaters, nitrogen supply part, laser system. This system uses the dual laser and 3D scanner made in $Solutionix^{TM}$ to improve the precision and speed for large objects. The three-dimensional solid objects are made of polyamide powder. The investigation on each part of SMLS system is performed to determine the proper theirs design and the effect of experimental parameters on making the 3D objects. The temperature of the system has a great influence on sintering the polymer. Because the stability of the powder temperature prevents the deformation of each layer, the controls of the temperature in both the system and the powders are very important during the process. Therefore, we simulated the temperature distribution of build room using the temperature analysis with ANSYS program. Selected radiant heater is used to raise temperature of powder to melting point temperature. The laser parameters such as scan spacing, scan speed, laser power and laser delay time affect the production the 3D objects too. The combination of the slow scan speed and the high laser power shows the good results without the layer curling. The work is under way to evaluate the effect of experimental parameters on process and to produce the various objects. We are going to experiment continuously to improve the size accuracy and surface roughness.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.786-789
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• 1988

Partially occluded objects are recognized from a 2-D image through the use of maximum curvature points on the image boundary. The vertices of high curvature on an occluded object are classified by the objects which are hypothesized to be involved in the occlusion. A heuristic method is developed for computational speed. Two typical examples are given to illustrate the accuracy as well as the simplicity of the heuristic method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.596-600
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• 1986

This paper describes a capacitively reading apparatus for determining the angular orientation, speed and/or direction of rotary objects such as shaft, dial hand, counter wheel and the like. The apparatus consists of sensing device and circuit accompanying with said sensing device. The sensing device is provided by arranging many stationary electrodes lying substantially on a surface of a stationary plane member and by arranging rotary electrode lying substantially on a surface of rotary objects to be monitored, in which said rotary electrode is in confronting relationship to some stationary electrodes so as to construct unique capacitors according to the angular position of rotary objects. The angular position of said rotary electrode is determined by sets of stationary electrodes which are in confronting relationship to rotary electrode. A carrier signal is generated by scanning device while scanning said stationarelectrodes, whose periods are in corresponding relationship to said stationary electrodes, respectively. The periods of carrier corresponding to the angular position of said rotary electrode is modulated by a modulation signal generated by detecting device according to said rotary electrode. This apparatus is applied to automatically monitor any kind of storage tank, as well as to automatically read the conventional utility meters such as Watthour meters, Gas meters, Water meters, etc..

• 천문학논총
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• 제21권2호
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• pp.75-79
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• 2006

An alt-azimuth type mount system, developed at the Space Science and Technology Laboratory, Kyung Hee University, has been found to experience some difficulties in monitoring of the artificial space objects. Since the telescope installed on the alt-azimuth mount does not rotate on the same axis as the earth does, this mount system needs an instrument rotator to correct the field rotation. Although there are some commercial instrument rotators already in the market, those are not suitable for our system due to their low interchangeability. In this study, we have designed a new high speed instrument rotator and calculated the deformation of new designed system using structural analyses.

• 인터넷정보학회논문지
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• 제21권4호
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• pp.117-126
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• 2020

해상 객체 인식은 자율운항선박(MASS)의 지능형 보조 시스템으로써, 선장이 육안으로 해상 주변의 충돌 위험성이 있는 부유물을 확인하던 정보를 컴퓨터를 통해 자동으로 인식하여 사람이 확인하는 방법과 유사한 정확도로 인지하는 방법을 말한다. 선박 주변의 물체를 인식하는 방법으로 기존에는 레이더나 소나와 같은 장치로부터 수집된 정보를 통해 확인하였지만, 인공지능의 기술이 발달하면서 선박 지능형 CCTV를 통해 운항 항로에 있는 다양한 부유물을 인식하는 것이 가능하다. 하지만, 자율 선박의 다양한 요구사항과 복잡성 때문에 영상 데이터의 처리속도가 느려지게 된다면 원활한 서비스 지원은 물론 안전성도 보장할 수 없게 된다. 이러한 문제를 해결하고자 본 논문에서는 해상 객체를 검출하는 데 있어 영상 데이터의 연산량을 최소화하여 처리속도를 높이기 위한 연구를 진행하였다. 해상 객체 인식의 관심 영역을 확보하기 위해서는 일반적으로 수평선을 찾는데 기존 연구들은 허프 변환 알고리즘을 활용하지만 본 논문에서는 속도를 개선하기 위해 이진화 알고리즘을 최적화하여 실제 객체의 위치와 유사한 영역을 찾는 새로운 방법을 제안한다. 또한, 제안하는 방법의 유용성을 증명하기 위해 딥러닝 CNN을 활용하여 해상 객체 인식 시스템을 구현함으로써 알고리즘의 성능을 평가하였다. 제안하는 알고리즘은 기존 방법의 인식 정확도를 유지하면서 약 4배 이상의 빠른 성능을 얻을 수 있었다.