• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.3
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• pp.243-251
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• 2016

LiDAR data processing steps include noise removal, filtering, classification, segmentation, shape recognition, modeling, and quality assessment. This paper focuses on modeling and accuracy evaluation of 3D objects with curved surfaces. The appropriate modeling functions were determined by analyzing surface patch shape. Existing methods for modeling curved surface features require linearization, initial approximation, and iteration of the non-linear functions. However, proposed method could directly estimate the unknown parameters of the modeling functions. The results demonstrate feasibility of the proposed method. The proposed method was applied to the simulated and real building data of hemi-spherical and semi-cylindrical surfaces. The parameters and accuracy of the modeling functions were estimated. It is expected that the proposed method would contribute to automatic modeling of various objects.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.8
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• pp.394-406
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• 2008

Even though context is the most important feature in context-aware systems, the existing requirements engineering cannot support methodology for elicitation and specification of contexts. In this paper, we propose a requirements elicitation method and a requirements specification method for context-aware systems. Our requirements elicitation method is a 6-stepped, incremental, and iterative process. At the beginning steps in the process, we identify the requirements for business logic. Afterwards, we gather the requirements for context logic, model contexts, and identify subsystems. For requirements specification, we suggest a context-aware use case diagram, a context diagram for context modeling, and a context-type-use-case-dependency diagram for the traceability of use cases on the change of context types. We also introduce a case study that we apply our approaches to a real system, and a qualitative evaluation of our approaches. Our study will help stakeholders to efficiently elicit requirements for context-aware systems and to specify them clearly.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.3
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• pp.283-290
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• 2016

Recent, the construction of the multi-purpose double-deck tunnel is required to solve the flood protection and congested area at urban city. The multi-purpose double-deck tunnel is desperately needed for the introduction of efficient utilization of underground space in addition to the main feature of road capabilities. A basic review was performed for site selection to consider the control capability and features of road tunnel at the same time, and the processable flow in accordance with tunnels cross section of double deck tunnel. Site Selection Criteria for multi-purpose use of the double-deck tunnel has been proposed through the site selection criteria by use of the tunnels review. Also the estimation processable flow was performed to review the versatility of double-deck tunnel due to design of tunnel cross-section. Site Selection of double-deck tunnel from this study can be seen the need for a complex consideration through a variety of analyzes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.655-661
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• 2017

It is a very important task to extract character regions contained in various input color images, because characters can provide significant information representing the content of an image. In this paper, we propose a new method for extracting character regions from various input images using MCT features and an AdaBoost algorithm. Using geometric features, the method extracts actual character regions by filtering out non-character regions from among candidate regions. Experimental results show that the suggested algorithm accurately extracts character regions from input images. We expect the suggested algorithm will be useful in multimedia and image processing-related applications, such as store signboard detection and car license plate recognition.

• Journal of KIISE:Information Networking
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• v.35 no.2
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• pp.166-172
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• 2008

This paper proposes an autonomous decentralized frame synchronization system for Ad-hoc Inter-Vehicle Communication Network (IVCN). We have to consider the feature of Ad-hoc IVCN: "time variant" about the number and the location of vehicles and receive power in IVCN, frame timing, and fading. Proposed scheme is different from other decentralized synchronization systems that have association with a fixed base station, and from centralized Personal Communication Systems. This system includes an autonomous decentralized frame synchronization scheme for Ad-hoc IVCN, a high-speed algorithm, a protocol for a newly joining subscriber in IVCN, and a utilization of spread spectrum ranging for frame timing error of the system under highway conditions. Performance evaluation of proposed scheme is validated through simulation. It is shown that Ad-hoc IVCN can be carried out among one and surrounding vehicles in such environment.

• The KIPS Transactions:PartA
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• v.10A no.4
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• pp.321-330
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• 2003

This paper proposes an agent-based adaptive tutoring system that monitors learning process of learners' and provides learning materials dynamically according to the analyzed learning character. Furthermore, it uses fuzzy concept to evaluate learners' ability and to provide learning materials appropriate to the level of learners'. For this, we design a courseware knowledge structure systematically and then construct a fuzzy level set on the basis of it considering importance of learning targets, difficulty of learning materials and relation degree between learning targets and learning materials. Using agent, monitoring continually the learning process of learners 'inferencing to offer proper hints in case of incorrect answer in learning assesment, composing dynamically learning materials according to the learning feature and the evaluation of assesment, our system implements effectively adaptive instruction system. Moreover, appling the fuzzy concept to the system could naturally consider and ideal with various and uncertain items of learning environment thus could offer more flexible and effective instruction-learning methods.

• The KIPS Transactions:PartB
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• v.9B no.1
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• pp.105-112
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• 2002

In order to process video data effectively, we need to save its content on database and a content-based retrieval method which processes various queries of all users is required. In this paper, we present VRS(Video Retrieval System) which provides similarity query, SQBE(Scene Query By Example) query, and content-based retrieval by combining the feature-based retrieval and the annotation-based retrieval. The SQBE query makes it possible for a user to retrieve scones more exactly by inserting and deleting objects based on a retrieved scene. We proposed query language and query processing algorithm for SQBE query, and carried out performance evaluation on similarity retrieval. The proposed system is implemented with Visual C++ and Oracle.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.441-450
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• 2006

Recently, with the exponential growth of the number of Internet users, IP traffic which occupies more than 90 percent of the entire Internet traffic affects significantly to the performance of networks. Therefore, the design of the self-similar traffic generator reflected the feature of IP traffic is very important to design the networks efficiently and evaluate the performance of it correctly. In this paper, we design the self-similar traffic generator using OPNET. In order to implement the self-similar characteristics, ON-OFF sources with Pateto distribution are employed and aggregated. The designed self-similarity traffic generator is evaluated and verified with R/S plot, variance time(VT) plot under the various offered loads and the number of sources. It is expected that the designed self-similar traffic generator can be put to practical use when wire or wireless networks is designed and verified as well as it can be useful to decide the specific parameter value for Internet traffic modeling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.573-582
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• 2006

In this paper, we propose a hybrid two-stage AWG-based WDM-PON architecture in order to overcome the limitations of the existing PONs and single AWG-based WDM-PONs as well as to accomodate the new services and the expandability of network. The proposed architecture employs two-stage AWG for downstream transmission and single AWG and combiners for upstream one at RN. It also employs the separated fiber with multi-wavelength for both direction. It leads to high scalability, low cost, and high capacity for transmission. In downstream transmission, the transparency can be guaranteed since the traffic is transmitted to ONU through each channel. However, several ONUs share the channel for upstream one by using WDM/TDMA scheme because the asymmetrical feature of networks is considered. The performance of the proposed one is evaluated and compared with other architectures in terms of cost, network capacity and up/downstream bandwidth.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.217-227
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• 2010

To apply active RFID technology in the various kinds of industry, it needs to quickly transmit a large amount of data. ISO/IEC 18000-7 standard uses the 433.92MHz as single channel system and its transmit rate is just 27.8kbps, that is insufficient for a large amount of data transmission. To solve this problem, we designed a new data transmission protocol using 2.4GHz band. The feature of designed protocol is not only making over 255bytes data messages using the Burst Read UDB but also efficiently transmitting it. To implement this protocol, we use Texas Instruments's SmartRF04 develop kit and CC2500 transceiver as RF module. As an evaluation of 63.75kbytes data transmission, we demonstrate that transmission time of Burst Read UDB has improved as 17.95% faster than that of Read UDB in the ISO/IEC 18000-7.