• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.279-282
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• 2007

Typically a wireless sensor network consists of a number of nodes that sense surrounding environment and collaboratively work to process and route the sensing data to a sink or gateway node. We propose an architecture with support of multiple routers in IPv6-based Low-power Wireless Personal Area Network (6LoWPAN). Our architecture provides traffic load balancing and increases network lifetime as well as self-healing mechanism so that in case of a router failure the network still can remain operational. Each router sends its own Router Advertisement message to nodes and all the nodes receiving the messages can select which router is the best router with the minimum hop-count and link information. We have implemented the architecture and assert our architecture helps in traffic load balancing and reducing data transmission delay for 6LoWPAN.

• Composites Research
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• v.32 no.6
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• pp.342-348
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• 2019

Development of flame retarding polymer based materials has been studied actively due to the increase in use of polymers. The post treatment of manufactured fibers or the introduction of flame retardant into fibers is representative method for the way to improve the flame retardancy. Among the polymers, polyacrylonitrile (PAN), which is a precursor of carbon fiber, has been widely used for clothes. Due to low flame retardancy of PAN fiber (LOI value: 17~18%), the improvement of flame retardancy of PAN fiber is needed. In this review paper, we report preparation methods for the fabrication of post-treated (oxidization or chemical reaction) flame-retarding PAN fibers and composites composed of PAN and organic/inorganic materials (SiO₂, 2D materials or CNT).

• Convergence Security Journal
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• v.15 no.7
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• pp.103-110
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• 2015

The security of the data exchanged between sensor nodes in IoT (Internet of Things) environment becomes increasing. In the conventional IEEE 802.15.4, the key for secure communication between the sensor node and the sensor node and the PAN Coordinator or the sensor node is assumed to be pre-shared in advance. Especially, there is another problem in that sensor node authentication is not considered during the association process. In this paper, we propose a security scheme that solves the problems of previously proposed protocols with the pre-shared key for all devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1391-1396
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• 2010

Recently, communication components prefer Bluetooth or Zigbee for PAN. However, using these makes expensive and complicated products such as audio equipments, mobile phones, PC, etc. for transmitting simple messages with low rate. In this paper, we propose wireless communication method using ultrasonic in the audio frequency limit band with speakers and microphones which are in products. We suggest transmitting and receiving methods in the audio frequency limit band for transmitting data without affecting audio signal, and implement an ultrasonic communication modem. Finally, we verify the performance of the ultrasonic communication modem by experiments in an environment with background noise.

• Transactions of Materials Processing
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• v.9 no.6
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• pp.670-680
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• 2000

The purpose of this study is to provide the database of forming limit diagram applicable to the warm forming of oil pan. The test materials are SCP1 and SCP3C with the thickness of 1.4mm which is used for the oil pan of automobile. The testing temperature is 5$^{\circ}C$~15$0^{\circ}C$ which is In the range of practical usage. The results are the forming limit diagram limiting dome height and the maximum punch load at each temperature such as 5$^{\circ}C$, $25^{\circ}C$, 6$0^{\circ}C$, 9$0^{\circ}C$, 12$0^{\circ}C$ and 15$0^{\circ}C$. From these results, we can see that the forming limit curves are translated depending upon the temperature and that FLC at low temperature is higher than at high temperature. Both of limiting dome height and maximum punch load also decrease as the temperature increases. Present results can be useful for die trial and forming analysis as a tool of evaluating the forming severity for the sheet metal forming processes at the warm working condition by comparing the practical strains with FLC.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4325-4329
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• 2014

Background: The expatriate population in Qatar largely comprises workers from the Indian subcontinent which has a very high rate of oral malignancy. Social and cultural habits and as well premalignant risk factors in this population remain prevalent even after migration. Materials and Methods: This cross sectional study assessed the prevalence of risk factors and occurrence of oral precancerous lesions in a low income group expatriate community from the Indian subcontinent residing in Qatar. Results: Among the 3,946 participants screened for oral premalignant lesions 24.3% (958) were smokers and 4.3 % (169) were pan chewers while 6.3% (248) were users of both smoked and smokeless forms of tobacco. Significantly higher proportion of industrial laborers (49.9%) followed by drivers (24.1%) were found to be smokers (p=0.001). The prevalence of white lesions was higher in smokers versus non-smokers 3.5% versus 2.3% (p=0.111), however this difference was statistically non-significant. Red and white lesions were highly significant (i.e. 1.2 % and 10.9% respectively) in the subjects with pan chewing and smoking habits (p=0.001). A significant proportion (8.9%) of the subjects with pan chewing habit showed evidence of oral precancerous lesions (p=0.001). Conclusions: Even though smoking and pan chewing were two significant risk factors detected in this population, their prevalence and occurrence of premalignant lesions are low as compared to the studies conducted in their home countries.

• Korean journal of food and cookery science
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• v.23 no.6
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• pp.824-831
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• 2007

This study was conducted to investigate the quality characteristics of low-fat pork patties containing fat replacers. Pectin(PE) and potato starch(PO) were added as fat replacers and physicochemical properties of the patties were evaluated after oven-roasting or pan-frying. Uncooked and cooked pork patties formulated with the fat replacers were higher in moisture and ash content and lower in fat content than those of the control. The cooking yield and reduction in diameter of the patties were significantly improved by the addition of PE or PO and oven-roasting exhibited a higher cooking yield and lower reduction in diameter than pan-frying (p<0.05). Water holding capacity(WHC) and fat retention were highest in the patties formulated with PE, while the control had the lowest WHC when cooked by oven-roasting. The Hunter L (lightness) values were not different among the patties but the Hunter a (redness) and b (yellowness) values of the low fat pork patties were higher than those of the control and oven-roasting produced higher redness values than pan frying. Hardness and brittleness were lowest in the patties with PE, while cohesiveness and springiness showed no difference among the patties (p<0.05). The sensory analysis results showed that the use of PE or PO improved the overall acceptability of the low-fat pork patties. After 30 days of storage at $-20^{\circ}C$, pH and cooking yield decreased slightly, while hardness increased in all the patties.

• Animal cells and systems
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• v.6 no.3
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• pp.187-193
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• 2002

It has long been recognized that exposure to low levels of toxic chemicals could have beneficial effects, such as increased resistance to related chemicals or stimulation of growth or development. The notion of radiation hormesis, that exposure to low levels of ionizing radiation could produce beneficial effects, developed seriously in the late 1950’s, and was, to most radiation scientists, incredible. This was due in pan to the then prevailing ideas of radiobiological mechanisms, in part to the sweeping generalizations made by the leading proponents of the radiation hormesis concept, and in pan to the many failures to confirm reports of beneficial effects. More recent understanding of the mechanisms of radiation damage and repair, and discoveries of induction of gene expression by radiation and other genotoxic agents [the adaptive response] make it seem inevitable that under suitable conditions, irradiation will produce beneficial effects.

• Korean Journal of Remote Sensing
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• v.25 no.6
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• pp.517-529
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• 2009

Many satellite image fusion techniques have been developed in order to produce a high resolution multispectral (MS) image by combining a high resolution panchromatic (PAN) image and a low resolution MS image. Heretofore, most high resolution image fusion techniques have used IKONOS and QuickBird images. Recently, GeoEye-1, offering the highest resolution of any commercial imaging system, was launched. In this study, we have experimented with GeoEye-1 images in order to evaluate which fusion algorithms are suitable for these images. This paper presents compares and evaluates the efficiency of five image fusion techniques, the $\grave{a}$ trous algorithm based additive wavelet transformation (AWT) fusion techniques, the Principal Component analysis (PCA) fusion technique, Gram-Schmidt (GS) spectral sharpening, Pansharp, and the Smoothing Filter based Intensity Modulation (SFIM) fusion technique, for the fusion of a GeoEye-1 image. The results of the experiment show that the AWT fusion techniques maintain more spatial detail of the PAN image and spectral information of the MS image than other image fusion techniques. Also, the Pansharp technique maintains information of the original PAN and MS images as well as the AWT fusion technique.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.6
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• pp.517-526
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• 2015

Among the various image fusion or pan-sharpening methods, those wavelet-based methods provide superior radiometric quality. However, the fusion processing is not only simple but also flexible, since many low- and high-frequency sub-bands are often produced in the wavelet domain. To address this issue, a novel DT-CWT (Dual-Tree Complex Wavelet Transform) proportional to the fusion method by a WZP (Wavelet Zero-Padding) is proposed. The proposed method produces a single high-frequency image in the spatial domain that is injected into the LRM (Low-Resolution Multispectral) image. Thus, a wavelet domain fusion can be simplified to spatial domain fusion. In addition, in the proposed DT-CWTP (DT-CWT Proportional) fusion method, it is unnecessary to decompose the LRM image by adopting WZP. The comparison indicates that the proposed fusion method is nearly five times faster than the DT-CWT with SW (Substitute-Wavelet) fusion method, meanwhile simultaneously maintaining the radiometric quality. The conducted experiments with WorldView-2 satellite images demonstrated promising results with the computation efficiency and fused image quality.