• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.12
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• pp.2085-2091
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• 2003

An ultrasonic machining process has been known as efficient and economical means fer precision machining of glass or ceramic materials. However, because of its complexity, the mechanism of the machining process is still not well understood. Therefore, it is hard to optimize the process parameters effectively. The conventional ultrasonic machining which uses the abrasive slurry only, furthermore, is time-consuming and gives the relatively rough surface. In order to increase the material removal rate and improve the integrity of the machined surface, we have introduced the novel ultrasonic machining technique, Chemical-assisted UltraSonic Machining(CUSM). The desktop-style micro ultrasonic machine has been developed and the z-axis feed is controlled by the constant load control algorithm. To obtain the chemical effects, the low concentration HF(hydrofluoric acid) solution, which erodes glass, added to alumina slurry. Through various experiments and comparison with conventional results, the superiority of CUSM is verified. MRR increases over 200%, the surface roughness is improved and the machining load decreases dramatically.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.9
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• pp.793-798
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• 2015

This study investigates the effects of the size of copper sheets on the plastic deformation behavior in a microscale deep drawing process. Tensile tests are conducted on the copper sheets to study the flow stress of the materials with different grain sizes before carrying out the microscale deep drawing experiments. After the tensile tests, a novel desktop-sized microscale deep drawing system is used to perform the microscale deep drawing process. A series of microscale deep drawing experiments are subsequently performed, and the experimental results indicate that an increase in the grain size results in the reduction of the deformation load of the copper sheets due to the effects of the surface grain. The results also show that the blank holder gap improves both the formability of copper sheets and the material flow.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.502-507
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• 2015

In this study, a microscale drilling process was conducted to evaluate the cutting characteristics of functionally graded materials. A mixture of M2 and Cu powders were formed and sintered to produce disk specimens of various compositions. Subsequently, a microscale hole was created in the specimen by using a desktop-size micro-machining system. By using design of experiments and analysis of variance, it was found that the M2-Cu composition, spindle speed, and the interactions between these two factors had significant effects on the magnitude of cutting forces. However, the influence of feed rate on the cutting force was negligible. A mathematical model was established to predict the cutting force under a wide range of process conditions, and the reliability of the model was confirmed experimentally. In addition, it was observed that increasing the wt% of Cu in an M2-Cu specimen increased the high-frequency amplitude of cutting forces.

• The Journal of Korean Association of Computer Education
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• v.9 no.6
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• pp.65-78
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• 2006

Recently, there has been much research to develope and apply RFID technology, which has a kcy role in the upcoming ubiquitous society, in many fields such as physical distribution, traffic control, medical service, and so on. However, there has been little research on a ubiquitous education or learning including 'u-Campuses' and 'u-Libraries'. Based on the characteristics of RFlD, this paper proposes a system for English learning required in globalization age. RFID tags and sensors utilize wireless communications to track the location and status information of the user to deliver English situated learning services. The current RFID-based system should use quite a different rniddleware, compared with a general-purpose middleware on server or desktop. The RFID system is used on a mobile PDA and consists of essential APIs such as reader and tag control, queue, and filter management.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.7
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• pp.694-702
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• 2007

The SSWM(Software Switching Mechanism) of I-processor concept using non-real time in-house software simulation program is an effective method in order to develop the flight control law in desktop or HQS environment. And, this system has some advantages compare to HSWM(Hardware Switching Mechanism) such as remove the time delay effectiveness and reduce the costs of development. But, if this system loading to the OFP(Operational Flight Program), the OFP guarantee the enough throughput in order to calculate the two control law at once. Therefore, the HSWM(Hardware Switching Mechanism) of 2-processor concept is necessary. This paper addresses the concept of HSWM of the HQS-PC interface using TCP/IP(Transmission Control Protocol/Internet Protocol) communication based on flight control law of advanced supersonic trainer. And, the fader logic of TFS(Transient Free Switch) and stand-by mode of reset '0' type are designed in order to reduce the abrupt transient response and minimize the integrator effect in pitch axis. The result of the analysis based on HQS pilot simulation using HSWM reveals that the flight control systems are switching between two computers without any problem.

• Journal of Digital Contents Society
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• v.13 no.3
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• pp.401-412
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• 2012

Communication through smartphones is creating a new paradigm of mobile communication beyond the restrictions of mobility and space. The mobile instant messengers of the smartphone, which began on the desktop environment, are providing various communication features, including multimedia contents, texts, and voice. Kindergartens and nurseries are using Websites, phones, SMS, printed materials, handwritten notifications, etc. to communicate with the parents. IsPlus was developed to facilitate the communication between the parents and the teachers, including exchanges of pictures and videos, chatting, and attendance management using smartphones. This is meaningful in that it is an early smartphone mobile messenger for educational institutions for infants and preschoolers. This study presented a new approach to the development of a mobile messenger for a specific group of users by analyzing the user environment, communication types, application planning process and interface design development using storytelling.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.6 no.1
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• pp.29-35
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• 2012

Most Augmentative and Alternative Communication(AAC) use exclusive equipment or studied desktop, tablet PC based windows. Besides, the preceding study offers proper noun dictionary so, henceforward study has problem to innumerable proper noun processing. This paper suggests a method of proper noun processing using a mobile smart equipment. And via the button with virtual keyboard input method and the errors that can occur is also proposing a complementary way. AAC system to check availability for application on Android has been implemented. Experimental results, depending on user location and selection of proper nouns in the around could produce a sentence is derived.

• Journal of Integrative Natural Science
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• v.11 no.3
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• pp.148-153
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• 2018

In this paper, we propose a hybrid-recognition system to obtain the state information and control the Internet of Things (IoT) based smart devices using two recognitions. First, we use a facial recognition for checking the owner of the mobile devices, i.e., smartphones, tablet PCs, and so on, and obtaining the state information of the IoT based smart devices, i.e., smart cars, smart appliance, and so on, and then we use a fingerprint recognition to control them. Further, in the conventional system, the message of the state and control information between the mobile devices and smart devices is only exchanged through the cellar mobile network. Thus, we also propose a direct communication to reduce the total transmission time. In addition, we develop a testbed of the proposed system using smartphones, desktop computers, and Arduino vehicle as one of the smart devices. We evaluate the total transmission time between the conventional and direct communications and show that the direct communication with the proposed system has better performance.

• Nuclear Engineering and Technology
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• v.47 no.2
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• pp.176-186
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• 2015

Pattern classifications have become important tools for fault diagnosis in nuclear power plants (NPP). However, it is often difficult to obtain training data under fault conditions to train a supervised classification model. By contrast, normal plant operating data can be easily made available through increased deployment of supervisory, control, and data acquisition systems. Such data can also be used to train classification models to improve the performance of fault diagnosis scheme. In this paper, a fault diagnosis scheme based on semisupervised classification (SSC) scheme is developed. In this scheme, new measurements collected from the plant are integrated with data observed under fault conditions to train the SSC models. The trained models are subsequently applied to new measurements for fault diagnosis. In comparison with supervised classifiers, the proposed scheme requires significantly fewer data collected under fault conditions to train the classifier. The developed scheme has been validated using different fault scenarios on a desktop NPP simulator as well as on a physical NPP simulator using a graph-based SSC algorithm. All the considered faults have been successfully diagnosed. The results have demonstrated that SSC is a promising tool for fault diagnosis in NPPs.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.4
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• pp.505-516
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• 2015

This study investigated difference of product interest and its relation to consumers' innate innovativeness according to gender as well as compared the perceptive construct of products between male and female consumers. A survey involving male and female college students was conducted in the Daegu and Gyeongbuk areas in December 2013. Subsequently, 400 responses were analyzed using descriptive statistics, correlations, independent sample t-test, reliability analysis, ANCOVA, and multidimensional scaling. Among 45 products, male respondents showed a significantly high degree of interest over 12 categories such as watches, desktop computers, cars, sports products, and video games compared to females. The female sample showed a significantly high degree of interest for 29 product categories such as clothing, movies, skin care shops, cosmetics, eating-out, teeth whitening, coffee, cameras, and performances compared to males. Innovative male consumers were interested in traveling, movies, clothing, eating-out, running shoes, and wallets; however, female consumers' innovativeness was significantly related to previously determined items of interest. Two dimensions explaining the male consumers' products perception construct were 'hard versus soft' and 'usual versus special'. Instead, female consumers' were 'special versus usual' and 'expressive versus functional'.