• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.200-206
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• 2015

In order to verify the lift enhancement of the 2D hydrofoil with trailing edge rotor and check the ability of its practical use, experimental studies were conducted in the caviation tunnel using the test model with NACA0020 section. The three-component forces acting on the model could be measured by exclusively designed sting type multi-component load cell. The trailing edge of the model has been replaced with rotor which could be controlled by DC servo motor installed at the exterior of the tunnel. A typical effect of the trailing edge rotor has been introduced among the systematic experiments on various angular deviation of the model and the rotational velocity of the trailing edge rotor. It is appeared that the circulation control effect could be easily adjusted by selecting the rotational velocity of the trailing edge rotor and the lift force was augmented more than two times. Thus the proposed lifting device could be utilized as a novel high lifting device which has adjustability of lift force.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2498-2504
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• 2009

This paper compared the output limit value of the Korean weak electric field strength wireless device in the 8.2MHz band with the standard values of foreign countries. Through this, the study confirmed that the Korean regulation was lower by about 10-20dB than those of the USA or Europe. In order to prove this, the study measured outputs by entrusting the 8.2MHz EAS system to two measuring companies. As a result of these measurements, electric field strengths were shown to be $70.6dB{\mu}V/m$ and $68.3dB{\mu}V/m$ respectively, and these values were confirmed to exceed the current Korean standard of $59.8dB{\mu}V/m$. Accordingly, it is deemed necessary to review the specifications of the Korean standard in the 8.2MHz band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.475-485
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• 2010

This paper proposes a novel concept for a microstrip resonator that can function as a filter and as an antenna at the same time. The proposed structure consists of an outer ring, an open loop-type inner ring, a circular patch, and three ports. The frequencies where the proposed structure works as a filter and as an antenna, respectively, are determined primarily by the radius of the inner ring and the circular patch. The measured results show that, when the microstrip resonator operates as a filtering device, this filter has about 15.1 % bandwidth at the center frequency of 0.63 GHz and a minimum insertion loss of 1.5 dB within passband. There are three transmission zeros at 0.52 GHz, 1.14 GHz, and 2.22 GHz. In the upper stopband, cross coupling - taking place at the stub of the outer ring - and the open loop-type inner ring produce one transmission zero each. The circular patch generates the dual-mode property of the filter and another transmission zero, whose location can be easily adjusted by altering the size of the circular patch. The proposed structure works as an antenna at 2.7 GHz, showing a gain of 3.8 dBi. Compared to a conventional patch antenna, the proposed structure has a similar antenna gain. At the resonant frequencies of the filter and the antenna, high isolation(less than -25 dB) between the filter port and the antenna port can be obtained.

• Journal of Digital Contents Society
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• v.15 no.2
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• pp.197-207
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• 2014

Many people are now enjoying mobile games using various smartphone platforms. However, we have to develop games separately for each smart device platforms so far. Cocos2d-x, a game development framework is released to solve this problem. As a multiplatform version of the existing Cocos2d, Cocos2d-x can make one source code run on various platforms. It is an open software that is able to be used by everyone, and when using it, mobile games can be developed easily based on C++ and OpenGL. In this paper, we implemented a PC laboratory decorating game application, named ILove501, using Cocos2d-x. The 501 is a room number of our PC lab. ILove501 includes an educational feature of solving quizzes in order to highlight positive effects of game. For implementation of a multiplatform game, ILove501 was developed in Windows and iOS environment at the same time, and we verified the results of the execution by porting on a variety of devices such as Android, iPhone, iPad and Galaxy Tab.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.7
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• pp.308-316
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• 2002

In this paper, we propose a robust digital copyright-protection technique based on the concept of human auditory system. First, we propose a watermarking technique that accepts the various attacks such as, time scaling, pitch shift, add noise and a lot of lossy compression such as MP3, AAC WMA. Second, we implement audio PD(portable device) for copyright protection using proposed method. The proposed watermarking technique is developed using digital filtering technique. Being designed according to critical band of HAS(human auditory system), the digital filers embed watermark without nearly affecting audio quality. Before processing of digital filtering, wavelet transform decomposes the input audio signal into several signals that are composed of specific frequencies. Then, we embed watermark in the decomposed signal (0kHz~11kHz) by designed band-stop digital filer. Watermarking detection algorithm is implemented on audio PD(portable device). Proposed watermarking technology embeds 2bits information per 15 seconds. If PD detects watermark '11', which means illegal song. PD displays "Illegal Song" message on LCD, skips the song and plays the next song, The implemented detection algorithm in PD requires 19 MHz computational power, 7.9kBytes ROM and 10kBytes RAM. The suggested technique satisfies SDMI(secure digital music initiative) requirements of platform3 based on ARM9E core.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.10-15
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• 2017

Research interest has strongly focused on developing a method for effectively transmitting bio-signals over a distance using a wireless wearable device. In this paper, we describe a procedure for the design and fabrication of a wearable antenna based on embroidering conductive threads to clothing capable of transmitting electrocardiogram signals. 3D electromagnetic simulation software and embroidery software were used to design and fabricate the conductive thread-based antenna, respectively. The measurement results show that the reflection coefficient of the fabricated antenna prototype exhibits excellent antenna impedance matching characteristics of less than -10dB in the Zigbee 2.4GHz frequency band. We also verified that the electrocardiogram data could be effectively received and monitored in real-time by a receiver 220m away from the transmitter.

• Journal of Digital Contents Society
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• v.11 no.3
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• pp.299-306
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• 2010

According to development of Internet and computer graphics technology, Digital fashion technology makes virtual fitting service capable by reappearing of clothes in 3D. In this paper, We suggest that combined solution which you could use virtual fitting service with various device. For example, imaginary mirror(such as digital information display), pc, mobile in different situations such as store, internet shopping market, commercial. Users can experience imaginary mirror that is located in store or 3D virtual fitting service for digital fashion in internet shopping market, mobile application. In addition, We proposed the solution that user can send experienced virtual fitting service results to other person by image file form of MMS.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.6
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• pp.37-45
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• 1998

In this paper, we report the first three-dimensional simulation result of the transient enhanced diffusion(TED) of dopants in the ion-implanted silicon by employing our 3D semiconductor process simulator, INPROS system. In order to simulate three-dimensional TED redistribution of dopants in silicon, the dopant distributions after the ion implantation was calculated by Monte Carlo(MC) method, followed by finite element(FE) numerical solver for thermal annealing. Excellent agreement between the simulated 3D profile and the SIMS data has been obtained for ion-implanted arsenic and phosphorus after annealing the boron marker layer at 75$0^{\circ}C$ for 2 hours. Our three-dimensional TED simulation could successfully explain the reverse short channel effect(RSCE) by taking the 3D point defect distribution into account. A coupled TED simulation and device simulation allows reverse short channel effect on threshold to be accurately predicted.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1723-1725
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• 1999

This paper is the study for piezoelectric properties of PMN-PT-PZ composition for high power piezoelectric device. It needs the properties such as high mechanical quality factor(Qm), high electromechanical coupling coefficient(kp) and high dielectric strain constant$(d_31)$, and the stable electromechanical properties under high vibration level. For acquiring this results, the value of x is changed in 0.1Pb$(Mn_{1/3}Nb_{2/3})O_3$+(0.9-x)$PbZrO_3+xPbTiO_3$ composition to find MPB(morphotropic phase boundary), and the piezoelectric constants is measured by resonance-antiresonance frequency method, based on IRE Standard. Also, it is measured as a function of the amount of additive, $Nb_2O_5$. When the composition is applied to high power device, the electromechanical properties is measured by laser vibrometer to confirm the reliablity under high vibration level. From these results, PMN-PT-PZ composition is shown excellent properties and capacity of application to high power device.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.31-37
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• 2017

This paper investigates the effect of the rotational motion of a driving fluid generated by a rotational motion device at the inlet of a driving nozzle for a gas-liquid ejector, which is the main device used for ozonated ship ballast water treatment. An experimental apparatus was constructed to study the pressure and suction flow rate of each port of the ejector according to the back pressure. Experimental data were acquired for the ejector without rotational motion. Based on the data, a finite element model was then developed. The rotational motion of the driving fluid could improve the suction efficiency of the ejector based on the CFD model. Based on the CFD results, structure optimization was performed for the internal shape of the rotation induction device to increase the suction flow rate of the ejector, which was performed using the kriging technique and a metamodel. The optimized rotation induction device improved the ejector efficiency by about 3% compared to an ejector without rotational motion of the driving fluid.