• The Journal of the Acoustical Society of Korea
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• v.21 no.5
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• pp.446-454
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• 2002

This paper presents the Doppler Scanning technique which enables us to detect the relative positions of moving distributed sources using Doppler frequency shift estimate when the moving source consists of distributed sources with different signature frequencies. Doppler frequency shifts of characteristic frequencies of machinery noise sources such as ship's generator and propeller, with tine along CPA (Closest Point of Approach of moving source) are unique, and can be functioned with respect to each source position. Therefore, this technique can be applied to estimate the relative geometrical positions between machinery noise sources. The Extended Kalman Filter (EKF) which has a high frequency resolution with high time resolution, is adopted for improving accuracy of Doppler frequency shift estimate geometric resolution of machinery positions since machinery noise sources show in general low frequency band characteristics with limited spacial distance. The performance of the technique is examined by the numerical simulations and is verified by the experiment using loudspeaker sources on the roof of the car.

• Korean Institute of Interior Design Journal
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• v.25 no.1
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• pp.3-12
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• 2016

This study analyses characteristics of space to facilitate community centering on cases of collective houses in Japan and uses the results as basic data to activate collective houses as an alternative form of housing in our country. To identify the characteristics of space for active communities with collective living space, this study conducted a theoretical examination on collective houses and housing, derived territoriality, accessibility, comfort and safety as factors of community activation and analysed various cases, and the results are presented as follows: First, territoriality is a necessary condition for formation of community, and a confined and physical space. It indicates the proper size of a space and diverse spacial areas which meet the needs of residents with the proper size and amount of space (space which can accommodate diverse generations including women, the aged and the young, flexible space which changes according to the purposes and program, space which supports leisure and hobby activities, and space which can accommodate outsiders). Second, accessibility indicates an environment which supports residents' easy use of space. As the more accessible it is, the higher the frequency of its use, spatial factors (piloti, backyards, benches and tables) should be provided, community space should be arranged in a central or decentralized way and community living space should be made for each floor. As for exits, accessibility should be considered in every way; entrances connected with community spaces, open entrances and entrances accessible from outside or individual living spaces. Third, comfort satisfies the physical and mental needs of residents through separation of floors and flows between the community and individual spaces for privacy and formation of eco-friendly spaces including vegetable gardens, gardens and plant arrangements. Fourth, safety should be considered for a higher quality environment with psychological stability and comfort, for which the following are recommended: installation of hand-rails, removal of thresholds, spacial design for the socially weak, duplex and open type structures for community space, open stages and halls, as well as indoor and outdoor openness through the use of windows.

• Journal of the Korea Society of Computer and Information
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• v.21 no.8
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• pp.1-12
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• 2016

In this paper, we propose a very efficient reversible data hiding algorithm using spatial locality and the surface characteristics of image. Spacial locality and a variety of surface characteristics are present in natural images. So, it is possible to precisely predict the pixel value using the locality and surface characteristics of image. Therefore, the frequency is increased significantly at the peak point of the difference histogram using the precisely predicted pixel values. Thus, it is possible to increase the amount of data to be embedded in image using the spatial locality and surface characteristics of image. By using the proposed reversible data hiding algorithm, visually high quality stego-image can be generated, the embedded data and the original cover image can be extracted without distortion from the stego-image, and the embedding data are much greater than that of the previous algorithm. The experimental results show the superiority of the proposed algorithm.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.1
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• pp.37-44
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• 2002

An echo signal in the active sonar using a high frequency is mainly formed of a specular reflection from the surface of an object along with several equivalent scatter inside, which are characterized by the spatial distribution of the highlights on the object. This thesis proposed a model in which the synthesized echo signal can be expressed as a distributed simulated target. The proposed model is obtained after composing a signal based on the movement of highlights relative to the aspect angle from the discontinuous point of an external hull with a strong reflection from a spheroid underwater target. Because the proposed algorithm includes a synthesis of the signals related to the highlight spacial distribution, it can be applied to all kinds of systems used at a short range, and similar results were obtained to the actual measured results of all reflected signals in previous literature referring to the irregular factor application of an envelope.

• Journal of Navigation and Port Research
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• v.29 no.4
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• pp.341-347
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• 2005

A unique technique to extract the phase in time domain is proposed in order to measure the time parameters such as speed and depth by transmitting sound and electric waves. In the signal analysis processing, the phase of pulse signal can be transformed and digitalized with local data in real time without the effect of direct current bias and Nyquist limits. This method is sensitive to base frequency of pulse signal with high spacial resolution and is effective to compare two signals which have different forms. It is expected that the phase analysis technique will be applied to the measurement of the speed and depth accurately by ultrasonic pulse signal in water.

• Journal of the Korean Institute of Educational Facilities
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• v.23 no.6
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• pp.19-26
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• 2016

In this study, moving awareness of students having different physical conditions in homebase and attitudes of students to spacial use in user's aspect were analyzed. As shown in the results, the dissatisfaction degree of the second grade using homebase type was higher than the first and the third grades using exclusive space for a class, homeroom type. The necessity of exclusive space for a class was highly shown in the second grade students. Students of the first and the third grades showed similar pattern in using frequency of homeroom. The results showed that behavior pattern of students was different with their physical conditions. Especially, factors showing obvious differences between the two groups were possession awareness of their belongings, tendency to route choice of high frequency, stay awareness of main stay in time to rest and point of time using restroom. These results will be useful to design various models in variation type of schools.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.2
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• pp.4-10
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• 1993

In mobile radio communication, propagation paths are time or spacial varying because of the motion of mobile unit. The propagation path loss not only involves frequency and distance but also the antenna height at both the base station and the mobile unit, terrain configuration, and the man made en- vironment. Thhese additional factors make the prediction of propagation path loss of mobile radio signals more difficult. In this paper, it is measured field strenght of mobile radio signals in Daejeon and Seoul area, also calculated local median, 500m sample mean, and stadard deviation. As the result of analysis, it can be seen that propagation path loss of measured data is similiar to predicted field strength, especially local median is dependent upon base antenna height, terrain configuration and the man-made environment. The standard deviation has been noted to lie between 2 and 10 dBuV.

• Journal of architectural history
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• v.9 no.2 s.23
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• pp.7-17
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• 2000

The purpose of this study is the analysis of 'perpendicular crossing Dori' with a structural character of Ddeulzip in Andong cultural area. There are many structural methods to solve the problems of Ddeuljip which is connected space in the rectangular type. There are 'Slope Base', 'Woosangak' roof, 'Seosangak' roof, and '4 beam roof framing' Moreover, they have been used 'perpendicular crossing Dori'. Its characters are as follows ; 1. The 'perpendicular crossing Dori' structure is occurred in different depth of width and length space of 'ㄱ' typed plan. At that time the beam of width is crossed in the middle of the beam of length without the order under them. 2. The 'perpendicular crossing Dori' structure is the method of free depth of width in regular distance of column which is different from general usage of balcony order. 3. The 'perpendicular crossing Dori' structure is founded north-western area of Andong Cultural Area(Bonghwa, Andong, Youngju, and Yeacheun). The best old sample was in Andong(16C) and the next is Yeacheun(17C) and the last is Bonghwa(18C). 4. The frequency in use of roof type of 'perpendicular crossing Dori' structure is 64% of 'Seosangak' and 36% of 'Woosangak'. The sample of 'Woosangak' house of 'perpendicular crossing Dori' structure is concentrated in Bonghwa. 5. The best merit of the 'perpendicular crossing Dori' structure is usage of double swing window in front of Anbang, It is the spacial success which overcomes the structural limits. And it is the structural rationality.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.1
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• pp.52-62
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• 2005

The objectives of this research is searching for the improvement scheme of spacial use of the Nature Environmental Conservation and its Utilization Facility through the analysis of those existing facilities from the structural and operational view points. In this study, firstly, analysis is commencing with the distinction of lawful and operational concepts of Nature Environmental Conservation and its Utilization Facility. In law, the concept is defined as an individual facility, while practical use of the concept has been understood as a collective space itself. Secondly, frequency tables in regard to the duration of the construction, types of location and objectives, and facility numbers are prepared on the basis of 53 cases of completed and under construction facilities. Conclusively, through the comparisons of facilities of Korea, United Kingdom and Germany, the future considerations on the improvement of the facilities in light of structural and operational aspects has been recommended. In structural view, ecological conservation aspect should be considered from the planning stage of the facility. And at the operational stage, various considerations should be given to the employment of facility experts and development of educational programs respectively.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.217-220
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• 1996

In this paper, we compare three mehods to obtain PSD of HRV - FFT, AR modeling, and residual integration. Using these methods we speculate the balances of the LP and HF powers of HRV at $0^{\circ}$, $45^{\circ}$, $90^{\circ}$ tilt levels of head-up tilt table for young and healthy 24 men. R peaks are located at the highest point of QRS complex detected from modified spacial velocity algorithm. In general FFT is the most fast way to obtain PSD but PSD from FFT has too many peaks and valleies. AR PSD can show frequency of ANS activity effectively but LF component of PSD is often invisible due to interference of VLF power. The residual integration method that decomposes the AR PSD is very efficient way to extract LF component. Applying the above three methods to HRV we can visualize the trend of PSD variations along tilt levels.