• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.195-199
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• 1998

본 논문은 감성측정평가 시뮬레이터 구축의 일환으로 개발한 3차원 시청각 환경 제시기가 생성하는 가상환경의 현실감 점도를 평가하는데 목적이 있다. 이를 위하여 가상환경의 최소 구성성분요소들로 Size, Length, Distance 등을 설정하였으며, 이들에 대하여 가상환경과 실제환경에서 각각 실험을 통해 피실험자들의 인식전도를 측정하였다. 실험에서 사용한 측정방법은 가상세계에 대한 인식실험을 위해 개발된 Size/Distance Estimation, Sketch Map, Object Search 방법 등을 사용하였으며, 가상환경과 실제환경에서 각각 도출된 실험결과의 차이를 토대로 3차원 시청각 환경 제시기의 현실감 수준을 평가하였다. 본 실험을 위해 구성한 피실험자의 집단은 컴퓨터 사용에 익숙한 20대 이공계열 84명(남:56, 여:28)의 학생들을 대상으로 하였다. 본 논문의 의의로는 3차원 시청각 환경 제시기가 생성하는 가상환경의 현실감 수준을 평가함으로써 개발 시스템의 보완 및 발전과 본격적인 감성공학 분야의 활용을 위한 지침을 마련하는데 있다.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.176-181
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• 2006

Experiments of Counter-Current Flow Limit(CCFL or Flooding) is performed to improve the drawbacks of Wallis' Correlation which neglects the effects of channel size, channel length, injection method and the boundary conditions at the inlet of liquid and gas phase. In this study, CCFL is observed by changing shape of porous plate using air and water. Results show that as the size of porous increases, CCFL with round shape of the porous plate decreases. In the present study, a CCFL correlation is developed and the CCFL map is proposed based on the present experimental results. developed by this experimental study.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.66.2-66.2
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• 2020

We propose a deep learning analysis technique with a convolutional neural network (CNN) to predict the evolutionary track of the Epoch of Reionization (EoR) from the 21-cm differential brightness temperature tomography images. We use 21cmFAST, a fast semi-numerical cosmological 21-cm signal simulator, to produce mock 21-cm maps between z = 6 ~ 13. We then apply two observational effects, such as instrumental noise and limit of (spatial and depth) resolution somewhat suitable for realistic choices of the Square Kilometre Array (SKA), into the 21-cm maps. We design our deep learning model with CNN to predict the sliced-averaged neutral hydrogen fraction from the given 21-cm map. The estimated neutral fraction from our CNN model has great agreement with the true value even after coarsely smoothing with broad beam size and frequency bandwidth and heavily covered by noise with narrow beam size and frequency bandwidth. Our results show that the deep learning analyzing method has the potential to reconstruct the EoR history efficiently from the 21-cm tomography surveys in future.

• Journal of Broadcast Engineering
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• v.21 no.2
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• pp.252-260
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• 2016

The performance of human detection system is affected by camera location and view angle. In 2D image acquired from such camera settings, humans are displayed in different sizes. Detecting all the humans with diverse sizes poses a difficulty in realizing a real-time system. However, if the size of a human in an image can be predicted, the processing time of human detection would be greatly reduced. In this paper, we propose a method that estimates human size by constructing an indoor scene in 3D space. Since the human has constant size everywhere in 3D space, it is possible to estimate accurate human size in 2D image by projecting 3D human into the image space. Experimental results validate that a human size can be predicted from the proposed method and that machine-learning based detection methods can yield the reduction of the processing time.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.1
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• pp.168-182
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• 2019

The objectives of this study were to examine the production processes and methods of "Forest Type Map Actualization Production (Database (DB) Construction Work Manual)" (Work Manual) identify issues associated with the production processes and methods, and suggest solutions for them by applying evaluation items to a 1:5k digital forest type map. The evaluation items applied to a forest type map were divided into zoning and attributes, and the issues associated with the production processes and methods of Work Manual were derived through analyzing the characteristics of the stand structure and fragmentation by administrative districts. Korea is divided into five divisions, where one is set as the area changed naturally and the other four areas set as the area changed artificially. The area changed naturally has been updated every five years, and those changed artificially have been updated annually. The fragmentation of South Korea was analyzed in order to examine the consistency of the DB established for each region. The results showed that, in South Korea, the number of patches increased and the mean patch size decreased. As a result, the degree of fragmentation and the complexity of shapes increased. The degree of fragmentation and the complexity of shapes decreased in four regions out of 17 regions (metropolitan cities and provinces). The results indicated that there were spatial variations. The "Forest Classification" defines the minimum area of a zoning as 0.1ha. This study examined the criteria for the minimum area of a zoning by estimating the divided object (polygon unit) in a forest type map. The results of this study revealed that approximately 26% of objects were smaller than the minimum area of a zoning. The results implied that it would be necessary to establish the definition and the regeneration interval of "Areas Changed Artificially and Areas Changed Naturally", and improve the standard for the minimum area of a zoning. Among the attributes of Work Manual, "Species Change" item classifies terrain features into 52 types, and 43 types of them belong to stocking land. This study examined distribution ratios by extracting species information from the forest type map. It was found that each of 23 species, approximately 53% of species, occupied less than 0.1% of Forested land. The top three species were pine and other species. Although undergrowth on unstocked forest land are classified in the terrain feature system, their definition and classification criteria are not established in the "Forest Classification" item. Therefore, it will be needed to reestablish the terrain feature system and set the definitions of undergrowth.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1421-1434
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• 2020

The frequency and intensity of heatwaves have been increasing due to climate change. Since urban areas are more severely damaged by heatwaves as they act in combination with the urban heat island phenomenon, every possible preparation for such heat threats is required. Many overseas local governments build heat maps using a variety of spatial information to prepare for and counteract heatwaves, and prepare heatwave measures suitable for each region with different spatial characteristics within a relevant city. Building a heat map is a first and important step to prepare for heatwaves. The cases of heat map construction and thermal environment analysis involve various area distributions from urban units with a large area to local units with a small area. The method of constructing a heat map varies from a method utilizing remote sensing to a method using simulation, but there is no standard for using differentiated spatial information according to spatial scale, so each researcher constructs a heat map and analyzes the thermal environment based on different methods. For the above reason, spatial information standards required for building a heat map according to the analysis scale should be established. To this end, this study examined spatial information, analysis methodology, and final findings related to Korean and oversea analysis studies of heatwaves and urban thermal environments to suggest ways to improve the utilization efficiency of spatial information used to build urban heat maps. As a result of the analysis, it was found that spatial, temporal, and spectral resolutions, as basic resolutions, are necessary to construct a heat map using remote sensing in the use of spatial information. In the use of simulations, it was found that the type of weather data and spatial resolution, which are input condition information for simulation implementation, differ according to the size of analysis target areas. Therefore, when constructing a heat map using remote sensing, spatial, spectral, and temporal resolution should be considered; and in the case of using simulations, the spatial resolution, which is an input condition for simulation implementation, and the conditions of weather information to be inputted, should be considered in advance. As a result of understanding the types of monitoring elements for heatwave analysis, 19 types of elements were identified such as land cover, urban spatial characteristics, buildings, topography, vegetation, and shadows, and it was found that there are differences in the types of the elements by spatial scale. This study is expected to help give direction to relevant studies in terms of the use of spatial information suitable for the size of target areas, and setting monitoring elements, when analyzing heatwaves.

• Journal of the Ergonomics Society of Korea
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• v.29 no.5
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• pp.771-782
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• 2010

Today, the number of elderly drivers who use navigation is increasing with the growing number of elderly drivers. The purpose of this study is to provide guidelines on the interface of car navigation for elderly users. To extract significant factors which were distinguished between young and elderly users, both young and elderly users executed the driving test by installing two car navigation alternatives. The analysis was conducted through t-test. The results show that significantly different factors were the number and the meaning of the menu items in the initial screen, the location and the meaning of the menu icons in the map screen, the ease of search of the menu and the text size in the menu screen. Improvements for the factors of the initial screen and map screen were made with reference to ergonomic guidelines, and suggested through experiments comparing design alternatives for the menu screen. Design alternatives were made through a combination of investigative variables, and the analysis was conducted through ANOVA. The results show that Alternative 7 (the location of the tab was placed at the bottom, menu representation was done with the text font size of 18pt and the location of menu navigation icons was shown at the upper left) was preferred in terms of user's preference and the execution time. So if the suggested menu for elderly users are added to the existing design, both users will satisfy their desires. The guidelines suggested in this study will help the designer of car navigation take elderly users into consideration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12A
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• pp.964-974
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• 2003

With increasing use of a personal mobile computer. the Mobile IPv6 is one of the main protocols that support mobility and complies with IPv6 specification. Similar to the mobile IPv6, the mobile IPv6 also has limitations on fast moving condition. The Hierarchical Mobile IPv6 is a solution that overcomes these limitations. The Hierarchical Mobile IPv6 is a micro mobility protocol that supports fast mobile IP handover and reduces signaling overhead with Mobility Anchor Point(MAP). But until now no paging method is applied to the Hierarchical Mobile IPv6 to reduce unnecessary signaling overhead and power consumption of mobile nodes. So, the paging mechanism for the Hierarchical Mobile IPv6 is proposed in this paper. the mechanism is implemented by making use of the destination option header and extension function and the last location algorithm. The results show that the Hierarchical Mobile IPv6 with the paging ability reduces the traffic of mobile networks by removing unnecessary binding update packet generated whenever handover takes place. Also, the larger the paging size is. the less the number of BU(Binding Update) massage generated.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.90-96
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• 2017

Due to the merit of having wide range with low cost, HF radar's ship detection and tracking research as maritime surveillance system has been recently studied. Many ship detection and tracking algorithms have been developed so far, however, performance comparison cannot be conducted properly because the states of target ships (such as moving path, size, etc.) differ from each study. In this paper, we propose a simulator based on compact HF radar, which generates data according to the size and moving path of target ship. Given the generated data with identical ship state, it is possible to conduct performance comparison. In order to validate the proposed simulator, the simulated data has been compared with real data collected by the SeaSonde HF radar sites. As a result, it has been shown that our simulated data resembles the real data. Therefore, the performance of various detection or tracking algorithms can be compared and analyzed respectively by using our simulated data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1C
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• pp.81-89
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• 2003

For improving the performance of noise suppression in tactical communication environments, an enhanced MELP vocoder is suggested, in which an acoustic noise suppressor is integrated into the front end of the MELP algorithm, and an FEC code into the channel side of the MELP algorithm. The acoustic noise suppressor is the modified IS-127 EVRC noise suppressor which is adapted for the MELP vocoder. As for FEC, the turbo code, which consists of rate-113 encoding and BCJR-MAP decoding algorithm, is utilized. In acoustic noise environments, the lower the SNR becomes, the more the effects of noise suppression is increased. Moreover, The suggested system has greater noise suppression effects in stationary noise than in non-stationary noise, and shows its superiority by 0.24 in MOS test to the original MELP vocoder. When the interleave size is one MELP frame, BER 10-6 is accomplished at channel bit SNR 4.2 ㏈. The iteration of decoding at 3 times is suboptimal in its complexity vs. performance. Synthetic quality is realized as more than MOS 2.5 at channel bit SNR 2 ㏈ in subjective voice quality test, when the interleave size is one MELP frame and the iteration of decoding is more than 3 times.