• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.64-83
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• 2012

The number of smart phone users is rapidly growing due to recent increase in wireless Internet usage, development of a wide variety of applications, and activation of M2M (Machine to machine) services. Although the smart phone offers benefits of mobility and convenience, it also has serious security problems. To utilize M2M services in the smart phone, a flexible integrated authentication and access control facility is an essential requirement. To solve these problems, we propose a context-aware single sign-on and access control system that uses context-awareness, integrated authentication, access control, and an OSGi service platform in the smart phone environment. In addition, we recommend Fuzzy Logic and MAUT (Multi-Attribute Utility Theory) in handling diverse contexts properly as well as in determining the appropriate security level. We also propose a security system whose properties are flexible and convenient through a typical scenario in the smart phone environment. The proposed context-aware security system can provide a flexible, secure and seamless security service by adopting diverse contexts in the smart phone environment.

• Journal of the Korean Society for Heat Treatment
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• v.8 no.1
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• pp.53-64
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• 1995

A study was made to characterize the microstructures and mechanical properties of the base metal and the heat-affected zone(HAZ) in Cu-bearing HSLA-100 steel. The Gleeble thermal/mechanical simulator was used to simulated the weld HAZ. The relationship between microstructure and toughness of HAZ was studied by impact test, O. M, SEM, TEM, and DSC. The toughness requirement of military specification value was met in all test temperatures for the base metal. The decrease of HAZ toughness comparing to base plate is ascribed to the coarsed-grain and the formation of bainite. Obliquely sectioned Charpy specimens show that secondary crack propagate easily along bainite lath. Improved toughness(240J) at HAZ of $Tp_2=950^{\circ}C$ is due to the fine grain, and reasonable toughness(160~00J) in the intercritical reheated HZA is achieved by the addition of small amount of carbon which affects the formation of "M-A". Cu precipitated during ageing for increasing the strength of base metal is dissolved during single thermal cycle to $1,350^{\circ}C$ and is precipitated little on cooling and heating during subsequent weld thermal cycle. Thus, the decrease of toughness does not occur owing to the precipitation of Cu.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.269-275
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• 2006

In the design of bridge piers in seismic area, the ductility requirement is one of the most important design criteria. In order to enhance the seismic performance of RC columns, it is necessary to make the ductility of columns larger by covering RC columns with steel tubes or confining RC columns by arranging transverse reinforcement such as hoop ties closely. Concrete encased composite columns can be utilized for bridge piers especially in seismic area. In this paper, finite element analyses are performed to study the nonlinear behavior of concrete encased composite columns with single core steel or multiple steel elements under static and quasi-static loads. The cross-sections of these specimens ate composed of concrete-encased H-shaped structural steel columns and a concrete-encased circular tube with partial in-filled concrete. Test parameters were the amount of the transverse reinforcement, encased steel member, and loading axis. Through the comparison between FE analyses and test results, adequate material models for confined concrete and unconfined concrete ate investigated. After getting the proper analysis models for composite columns, several parameters are considered to suggest design considerations on the details of composite piers.

• Korean Journal of Remote Sensing
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• v.19 no.3
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• pp.255-261
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• 2003

Recently, the enormous increase in the volume of remotely sensed data is being acquired by an ever-growing number of earth observation satellites. The combining of diversely sourced imagery together is an important requirement in many applications such as data fusion, city modeling and object recognition. Aerial triangulation is a procedure to reconstruct object space from imagery. However, since the different kinds of imagery have their own sensor model, characteristics, and resolution, the previous approach in aerial triangulation (or georeferencing) is purformed on a sensor model separately. This study evaluated the advantages of aerial triangulation of large number of images from multi-sensors simultaneously. The incorporated multi-sensors are frame, push broom, and whisky broom cameras. The limits and problems of push-broom or whisky broom sensor models can be compensated by combined triangulation with other sensors The reconstructed object space from multi-sensor triangulation is more accurate than that from a single model. Experiments conducted in this study show the more accurately reconstructed object space from multi-sensor triangulation.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.76-85
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• 2019

We introduce a vision-based object detection method for real-time video surveillance system in low-end edge computing environments. Recently, the accuracy of object detection has been improved due to the performance of approaches based on deep learning algorithm such as Region Convolutional Neural Network(R-CNN) which has two stage for inferencing. On the other hand, one stage detection algorithms such as single-shot detection (SSD) and you only look once (YOLO) have been developed at the expense of some accuracy and can be used for real-time systems. However, high-performance hardware such as General-Purpose computing on Graphics Processing Unit(GPGPU) is required to still achieve excellent object detection performance and speed. To address hardware requirement that is burdensome to low-end edge computing environments, We propose sub-frame analysis method for the object detection. In specific, We divide a whole image frame into smaller ones then inference them on Convolutional Neural Network (CNN) based image detection network, which is much faster than conventional network designed forfull frame image. We reduced its computationalrequirementsignificantly without losing throughput and object detection accuracy with the proposed method.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.245-248
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• 2011

A multi pulse rocket motor(MPRM) has several advantages compared to the single one. The range and the terminal velocity of the guided missile can be remarkably increased by the application of the pulse separation device(PSD) to the solid rocket motor which resulted in appropriate thrust distribution. In this study, the full scale heavy type dual pulse rocket motor with the bulkhead type PSD was designed, manufactured, and fire-tested. The bursting time and pressure of PSD were analyzed by the pressure, thrust and vibration results of static fire tests. As a result, the design requirement was verified that bursting pressure is lower than 30% of 2nd pulse operating pressure.

• Smart Structures and Systems
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• v.7 no.5
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• pp.365-378
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• 2011

Piezo-based active structural health monitoring (SHM) requires amplifiers specifically designed for capacitive loads. Moreover, with the increase in number of applications of wireless SHM systems, energy efficiency and cost reduction for this type of amplifiers is becoming a requirement. General lab grade amplifiers are big and costly, and not built for outdoor environments. Although some piezoceramic power amplifiers are available in the market, none of them are specifically targeting the wireless constraints and low power requirements. In this paper, a piezoceramic transducer amplifier for wireless active SHM systems has been designed. Power requirements are met by two digital On/Off switches that set the amplifier in a standby state when not in use. It provides a stable ${\pm}180$ Volts output with a bandwidth of 7k Hz using a single 12 V battery. Additionally, both voltage and current outputs are provided for feedback control, impedance check, or actuator damage verification. Vibration control tests of an aluminum beam were conducted in the University of Houston lab, while wireless active SHM tests of a wind turbine blade were performed in the Harbin Institute of Technology wind tunnel. The results showed that the developed amplifier provided equivalent results to commercial solutions in suppressing structural vibrations, and that it allows researchers to perform active wireless SHM on moving objects with no power wires from the grid.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.586-589
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• 2012

Web Services have been utilized in a wide variety of applications and have turned into a key technology in developing business operations on the Web. Originally, Web Services can be exploited in an isolated form, however when no single Web Service can satisfy the functionality required by a user, there should be a possibility to compose existing services together in order to fulfill the user requirement. However, since the same service may be offered by different providers with different non-functional Quality of Service (QoS), the task of service selection for Web Service composition is becoming complicated. Also, as Web Services are inherently unreliable, how to deliver reliable Web Services composition over unreliable Web Services should be considered while composing Web Services. In this paper, we propose an approach on a QoS-aware Web Service selection for reliable Web Service composition. In our approach, we select and classify Web Services using Decision Tree based on QoS attributes provided by the client. Service classifier will improve selection of relevant Web Services early in the composition process and also provide flexibility to replace a failed Web Services with a redundant alternative Web Services, resulting in high availability and reliability of Web Service composition. We will provide an implementation of our proposed approach along with efficiency measurements through performance evaluation.

• Archives of Craniofacial Surgery
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• v.21 no.6
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• pp.351-356
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• 2020

Background: We have devised a novel surgical method, termed as temporalis muscle tendonperiosteum (T-P) compound surgical method, by modifying pre-existing techniques. Our method is characterized by elevation of temporalis muscle tendon and the periosteum of the mandibular ramus as a single compound. Here, we describe the concept and clinical outcomes of our method. Methods: We conducted both a cadaveric study and a clinical study. First, we used four human cadavers (two males and two females) to confirm the anatomy of the temporalis muscle tendon and availability of sufficient length extension through the elevation of the T-P compound. Moreover, we obtained measurements of the mouth angle and the philtrum angle from a total of six patients (two males and four females) and compared them between preoperatively and postoperatively. Results: The mean length of the periosteal portion was measured as 2.43± 0.15 cm (range, 2.2-2.6 cm). There was an improvement in the mouth angle postoperatively as compared with preoperatively (7.2°± 3.0° vs. 14.5°± 4.7°, respectively). Moreover, there was also an improvement in the philtrum angle postoperatively as compared with preoperatively (7.2°± 3.4° vs. 17.2°± 6.5°, respectively). Conclusion: Our method is a simple, minimally-invasive modality that is effective in achieving good clinical outcomes. Its advantages include an ability to achieve a firm extension of the temporalis muscle tendon as well as a lack of requirement for a donor site that may cause complications.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.232-240
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• 2022

To fulfill user expectations, the rapid evolution of software techniques and approaches has necessitated reliable and flawless software operations. Aging prediction in the software under operation is becoming a basic and unavoidable requirement for ensuring the systems' availability, reliability, and operations. In this paper, an improved evolutionary computing-driven extreme learning scheme (ECD-ELM) has been suggested for object-oriented software aging prediction. To perform aging prediction, we employed a variety of metrics, including program size, McCube complexity metrics, Halstead metrics, runtime failure event metrics, and some unique aging-related metrics (ARM). In our suggested paradigm, extracting OOP software metrics is done after pre-processing, which includes outlier detection and normalization. This technique improved our proposed system's ability to deal with instances with unbalanced biases and metrics. Further, different dimensional reduction and feature selection algorithms such as principal component analysis (PCA), linear discriminant analysis (LDA), and T-Test analysis have been applied. We have suggested a single hidden layer multi-feed forward neural network (SL-MFNN) based ELM, where an adaptive genetic algorithm (AGA) has been applied to estimate the weight and bias parameters for ELM learning. Unlike the traditional neural networks model, the implementation of GA-based ELM with LDA feature selection has outperformed other aging prediction approaches in terms of prediction accuracy, precision, recall, and F-measure. The results affirm that the implementation of outlier detection, normalization of imbalanced metrics, LDA-based feature selection, and GA-based ELM can be the reliable solution for object-oriented software aging prediction.