• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1108-1119
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• 2016

This paper presents the spectral analysis and radiation pattern of low-frequency electromagnetic(EM) leakage signals according to the fundamental operations of smartphones. The EM leakage signals generated by the activation of four I/O sensor modules such as a touch-screen, a camera, a microphone and a speaker are captured by the commercial near-field magnetic probe with 1cm spatial resolution. The analysis results show that the leakage of the EM wave occurs strongly around the activated I/O sensor modules, AP(Application Processor) and memory modules. Also, the distinguishable frequency characteristic is shown in each spectrum of EM leakage signals.

• Journal of Energy Engineering
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• v.17 no.2
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• pp.100-106
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• 2008

Flameless fiber mat catalytic burners have been known as an effective heat source in industrial drying processes since heat obtained from combustion can be transferred to absorptive body by far-infrared radiation. In order to extend the application of fiber mat catalytic burner, novel fiber mat catalytic burners were manufactured and combustion characteristics of them were investigated. For diffusive catalytic burners, the efficiency of combustion was significantly affected by the installation direction and the temperature of catalytic bed perimeter influenced on the diffusion rate of oxygen which determined the combustion efficiency of catalytic burner. It was seen in premixed catalytic combustion that air content in premixed fuel gas was optimized at slightly higher than theoretical amount of air. Combustion heat released higher than 70% by radiant heat in premixed catalytic combustion likewise diffusive catalytic combustion.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.805-811
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• 2008

This paper presents a design of RFID(Radio Frequency Identification) tag antenna which is available for a vehicle's side mirror and directivity characteristics by mr body. The proposed Tag antenna is designed symmetrical structure to improve the broad bandwidth characteristic and the readable range. A proposed tag antenna($30\;mm{\times}24\;mm{\times}1\;mm$) has resonant frequency at 910 MHz and bandwidth is 780 MHz ($540\;MHz{\sim}1320\;MHz$). The chip impedance is the 16 - $j131\;{\Omega}$ and the complex conjugate impedance of commercial chip has been used for tag antenna design. In order to evaluate effects of tag antenna for side view mirror's permittivity as well as car body(conductor), radiation pattern characteristics and readable range have been calculated and measured. The optimized position for a vehicle's RFID system has been observed in the inside of a side mirror and the calculated results show good agreement with the measured results.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.460-465
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• 2019

In this study, we aim to derive a solution from the structural analysis for electrical failure of single board computers for computing navigation information. By analyzing the characteristic factor, we identify that crack occur on the central processing unit board due to a certain structural problem, and that the physical effect by the crack make communication function be impossible to perform, which it causes booting error. In order to find the location of excessive stress causing the crack, structural analysis for the single board computer is done. From the structural analysis, the areas where stress concentration occurs are identified, and improvement methods changing the structures are developed. As a result, we shows that stresses are reduced entirely on the stress distribution for the improved structure. In addition, heat analysis shows that changing the structure to reduce stresses is not affect to the heat radiation, and the thermal resistance of the actual equipment is verified by measuring the temperature of the heat sink applied with the improved structure.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.489-496
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• 2019

In this paper, we design and fabricate an ultra small dual crossed dipole antenna operating at 2.4 GHz frequency. In order to miniaturize the size of the antenna so that it can be applied to a mobile device, a cross dipole is disposed on the upper two layers and a reflection plane, a horizontal matching circuit and a ground plane are arranged on each layer. The circuit was connected by a vertical through-hole. The size of the fabricated antenna is $21.61mm{\times}16.88mm{\times}1.27mm$, the measured reflection coefficient is -31.5 dB, and the bandwidth below -10 dB is 112 MHz. In addition, since the gain of the antenna is -4 dBi, it has the omnidirectional radiation characteristic, so it can be applied to various fields as an antenna for mobile devices.

• Korean Journal of Heritage: History & Science
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• v.48 no.3
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• pp.138-153
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• 2015

For preventing the biological damage domestically, insect damage control method using chemical medicine has been applied. However, it is trend to avoid existing chemical medicine such as Methyl bromide because of the problem of being harmful to human body and environment. Therefore, the research for new medicine to replace this has been done and the interest to the physical treatment such as temperature(high & low) treatment, hypoxic treatment, carbon dioxide treatment, and radiation treatment has increased. However the systematic application standard and way has not been established. Therefore, in this research, we are going to organize present condition of domestic cultural asset preventing biological damage after the 1980's. It will also consider the direction through the characteristic of technology, limit, and replacement medicine by examining the past research.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.21-26
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• 2020

In this paper, we investigated the characteristics of SF-MPAA depend on the structures of radiators when they were embroidered for realizing embroidered SF-MPAA. As increasing pitches by decreasing numbers of grids in length-direction and width-direction of the embroidered radiator the antenna gain and resonance frequency were trendingly decreased. However the characteristics of antenna were affected very much by the pitch in width-direction but affected relatively less by the pitch in length-direction. Therefore it was beneficial to decrease number of grids in length-direction to decrease conductor ratio. SLL was affected by the combination of length-direction pitch and width-direction pitch. The conductor ratio of embroidered radiator was determined by the ratio of pitch to embroidered thread thickness. When the ratio was less than 5 the conductor ratio was decreased rapidly. But when the ratio was larger than 5 the conductor ratio was decreased slowly and saturated.

• Journal of IKEEE
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• v.25 no.4
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• pp.607-612
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• 2021

This paper presents a novel CPW-fed UWB monopole paper antenna made by paper and copper tape. Through the simulation, the optimized antenna design parameters were obtained, and an antenna having an omni-directional radiation pattern and a gain of 2.2 dBi or more in the UWB frequency band of 3.1-10.6 GHz was designed. The antenna was manufactured using general A4 paper and copper tape, and the measurement result satisfies the return loss of -10dB or less in the UWB frequency band and confirm that the return loss characteristic was maintained even when the antenna plane was bent by 3 mm in the longitudinal direction. The proposed antenna is a wearable device that can provide services in the UWB band, and can be manufactured inexpensively by printing it with a conductive print on paper. So it can be used as a wearable antenna for UWB communication in various application fields such as logistics and disposable terminals.

• The Journal of the Acoustical Society of Korea
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• v.42 no.5
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• pp.388-394
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• 2023

When the vibration of the thin panel by exciting single point is used to radiate sound, the inherent vibration characteristic of the plate itself causes influence on the radiated sound. A conventional panel speaker system usually uses the single or double point excitations for generating the sound through the panel itself. The radiated sound can be easily distorted due to the modal characteristics of the plate so it is difficult to expect sufficient sound power or high radiation efficiency. In this paper, to achieve an immersive sound field, the multiple speaker zones on a thin panel are created with the limited number of actuators. The designated vibration field which can generates directional sound is realized by employing the vibro-acoustic inverse rendering methods. Actuators are arranged from the positions which have the advantage of implementing with multi-modal excitations. The location and number of actuators are compared with the location and number of controllable speaker zones by conducting numerical simulations.

• Korean Journal of Head & Neck Oncology
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• v.39 no.1
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• pp.45-48
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• 2023

Angiosarcoma is a very rare subtype of sarcoma. It mainly occurs in the head and neck, and cutaneous angiosarcoma in this region seems to be a distinctive neoplasm with characteristic clinicopathologic features that differ from those of angiosarcoma in other anatomical locations. The prognosis of angiosarcoma in the head and neck region is poor, and the risk of local recurrence and metastasis is high. We reconstructed an atypical angiosarcoma that presented as a solitary nodule with a shape suggestive of hemangioma on the cheek using a modified bilobed local flap. At a 12-month follow-up visit, the patient in this case showed successful recovery after radiation therapy.