• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.196-199
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• 2010

The human eyes are important facial landmarks for image normalization due to their relatively constant interocular distance. This paper introduces a novel approach for the eye detection task using optimal segmentation method for eye representation. The method consists of three steps: (1)edge extraction method that can be used to accurately extract eye region from the gray-scale face image, (2)extraction of eye region using labeling method, (3)eye localization based on intensity information. Experimental results show that a correct eye detection rate of 98.9% can be achieved on 2408 FERET images with variations in lighting condition and facial expressions.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.373-380
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• 1997

In order to implement the real-time operating systems for robot controller, this paper proposes a systematic method for implementing the real-time kernel under the DOS environment. So far, we designed the robot control software and its own operating system simultaneously. Though robot operating systems have simple structure, it allows the developer to have a surplus time and effort to implement complete robot systems. In addition to this, in most cases of this type, operating systems does not support multitasking function, thus, low level hardware interrupts are used for real-time execution. Subsequently, some kinds of real-time tasks are hard to implement under this environment. Nowadays, the operating systems for robot controller requires multitasking functions, intertask communication and task synchronization mechanism, and rigorous real-time responsiveness. Thus, we propose an effective and low costs real-time systems for robot controller satisfying the various real-time characteristics. The proposed real-time systems are verified through real implementation.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.43-46
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• 2008

Quad-Rotor, which consists of four blades, performs a flight task by controling each rotation speed of the four blades. Quad-Rotor blade making no use of cyclic pitch or collective one is a type of fixed-wing as different from helicopter blade. Although, Quad-Rotor is simple and easy to control for those reasons, blade configuration of the fixed wing is one of the critical factors in determining the performance of Quad-Rotor. In the present study, coefficients for thrust and power of Quad-Rotor blade were derived from the data acquired by using 6-component balances. Firstly, Measurements for aerodynamic force were conducted at various pitch angles (i.e., from 0$^{\circ}$ to 90$^{\circ}$ with the interval of 10$^{\circ}$). The blade used in this experiment has aspect ratio of 6 and chord length of 35.5 mm. Secondly, assembled-blade, which was an integral blade but divided into many pieces, was used in order to test aerodynamic forces along twist angles. The curve of thrust coefficient along pitch angle indicates a parabola form. Stall which occurs during wind tunnel test to calculate lift coefficient of airfoil does not generate. When deciding the blade twist angle, structural stability of blade should be considered together with coefficients of thrust and power. Those aerodynamic force data based on experimental study will be provided as a firm basis for the design of brand-new Quad-Rotor blade.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.3
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• pp.347-354
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• 2014

The color appearance of a yarn-dyed woven fabric depends on the color of the yarn as well as on the weave structure. Predicting the final color appearance or formulating the recipe is a difficult task, considering the interference of colored yarns and structure variations. In a modern fabric design process, the intended color appearance is attained through a digital color methodology based on numerous color data and color mixing recipes (i.e., color prediction models, accumulated in CAD systems). For successful color reproduction, accurate color prediction models should be devised and equipped for the systems. In this study, the final colors of yarn-dyed woven fabrics were predicted using six geometric-color mixing models (i.e., simple K/S model, log K/S model, D-G model, S-N model, modified S-N model, and W-O model). The color differences between the measured and the predicted colors were calculated to evaluate the accuracy of various color models used for different weave structures. The log K/S model, D-G model, and W-O model were found to be more accurate in color prediction of the woven fabrics used. Among these three models, the W-O model was found to be the best one as it gave the least color difference between the measured and the predicted colors.

• School Mathematics
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• v.4 no.2
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• pp.297-316
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• 2002

In this paper, a teaching unit on series of number sentences with patterns is designed according to Wittmann's perspectives. In this paper, series of number sentences wish patterns means number sentences in which some patterns are contained. especially, seven kinds of number sentences wish patterns are offered as basic materials, and fifteen tasks based on these basic materials are offered. These tasks are for ninth grade students and higher grade students. These tasks heap students to recognize patterns, and to understand mechanism underlying in those patterns by looking for patterns and proving whether these patterns are generally hold. As working on these tasks, students can reinforce meaning of algebraic expression, its manipulation, and concept of number series. Students also can reinforce mathematical thinking such as analogical thinking, deductive thinking, etc. In this point, this teaching unit reveal important objectives, contents, and Principles of mathematics education. This teaching unit can also be rich sources for student's activities. Especially, for each task's level is different, each student's personal ability is considered fully. Since teachers can know mathematical facet, psychological facet, and didactical facet holistically, this teaching unit can offer broad possibilities for experimental studies. SD, this leaching unit can be said to be substantial. In this paper, this leaching unit is not applied in classroom directly. Actually such applying in classroom is suggested as follow-up studies. By appling this teaching unit in various classroom, some effective informations for teaching this teaching unit and some particular phenomenons in those teaching processes can be identified, and this teaching unit can be revised to be better one.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5671-5693
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• 2017

With the rapid development of cloud computing, more and more data owners are motivated to outsource their data to cloud for various benefits. Due to serious privacy concerns, sensitive data should be encrypted before being outsourced to the cloud. However, this results that effective data utilization becomes a very challenging task, such as keyword search over ciphertexts. Although many searchable encryption methods have been proposed, they only support exact keyword search. Thus, misspelled keywords in the query will result in wrong or no matching. Very recently, a few methods extends the search capability to fuzzy keyword search. Some of them may result in inaccurate search results. The other methods need very large indexes which inevitably lead to low search efficiency. Additionally, the above fuzzy keyword search methods do not support access control. In our paper, we propose a searchable encryption method which achieves fuzzy search and access control through algorithm design and Ciphertext-Policy Attribute-based Encryption (CP-ABE). In our method, the index is small and the search results are accurate. We present word pattern which can be used to balance the search efficiency and privacy. Finally, we conduct extensive experiments and analyze the security of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.1
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• pp.72-79
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• 2003

Due to the improvements in circuit design technique and manufacturing technique, complexity of a circuit is growing along with the demand for memories with large capacities. Likewise, as a memory capacity gets larger, testing gets harder and testing cost increases, and testing process in chip development gets larger as well. Therefore, a research on an effective test algorithm to improve the chip yield rate in a short time period is becoming an important task. This paper proposes an effective, March C-algorithm based, test algorithm that can also be applied to a dual-port memory since it considers all the fault types, which can be occurred in a single-port as well as in a dual-port memory, without increasing the test length.

• Nuclear Engineering and Technology
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• v.44 no.5
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• pp.471-482
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• 2012

To assess the risk of nuclear power plant operation and to determine the risk impact of digital systems, there is a need to quantitatively assess the reliability of the digital systems in a justifiable manner. The Probabilistic Risk Analysis (PRA) is a tool which can reveal shortcomings of the NPP design in general and PRA analysts have not had sufficient guiding principles in modelling particular digital components malfunctions. Currently digital I&C systems are mostly analyzed simply and conventionally in PRA, based on failure mode and effects analysis and fault tree modelling. More dynamic approaches are still in the trial stage and can be difficult to apply in full scale PRA-models. As basic events CPU failures, application software failures and common cause failures (CCF) between identical components are modelled.The primary goal is to model dependencies. However, it is not clear which failure modes or system parts CCF:s should be postulated for. A clear distinction can be made between the treatment of protection and control systems. There is a general consensus that protection systems shall be included in PRA, while control systems can be treated in a limited manner. OECD/NEA CSNI Working Group on Risk Assessment (WGRisk) has set up a task group, called DIGREL, to develop taxonomy of failure modes of digital components for the purposes of PRA. The taxonomy is aimed to be the basis of future modelling and quantification efforts. It will also help to define a structure for data collection and to review PRA studies.

• Journal of Construction Engineering and Project Management
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• v.8 no.1
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• pp.10-21
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• 2018

Many construction projects involve a plethora of safety-related problems that can cause loss of productivity, diminished revenue, time overruns, and legal challenges. Incorporating data collection and analytics methods can help overcome the root causes of many such problems. However, in a dynamic construction workplace collecting data from a large number of resources is not a trivial task and can be costly, while many contractors lack the motivation to incorporate technology in their activities. In this research, an Android-based mobile application, Preemptive Construction Site Safety (PCS2) is developed and tested for real-time location tracking, trajectory prediction, and prevention of potential collisions between workers and site hazards. PCS2 uses ubiquitous mobile technology (smartphones) for positional data collection, and a robust trajectory prediction technique that couples hidden Markov model (HMM) with risk-taking behavior modeling. The effectiveness of PCS2 is evaluated in field experiments where impending collisions are predicted and safety alerts are generated with enough lead time for the user. With further improvement in interface design and underlying mathematical models, PCS2 will have practical benefits in large scale multi-agent construction worksites by significantly reducing the likelihood of proximity-related accidents between workers and equipment.

• Science of Emotion and Sensibility
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• v.15 no.3
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• pp.381-388
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• 2012

The purpose of this study is to check if LED lighting can be used as general lighting and examine the color rendering property of full color RGB LED lighting. CRI is one of the important properties of evaluating lighting. However the present CRI does not fully evaluate LED lightings. Firstly, the performance of a simple task was compared other than comparing CRI values for different lighting. For experimental preparation three types of lightings were used; standard D65 fluorescent tube, general household fluorescent tube, and RGB LED lighting. All three lightings show high error for Purple-Red. All three lightings show similar error for all hues and prove that color discrimination is not affected by the lighting. This proves that LED could be used as general lighting. Secondly, problems of the conventional CIE CRI method are considered and new models are suggested for the new lighting source. Each of the models was evaluated with visual experiment results obtained by the white light matching experiment. The suggested model is based on the CIE CRI method but replaces the color space model by CIELAB, color difference model by CIEDE2000, and chromatic adaptation model by CAT02.