• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.5
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• pp.418-429
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• 1996

The number of bits per message and the number of tones in the frequency-hopping sequence are determined by the available bandwidth and the data rate of each user. These parameters in turn determine the tone duration which strongly influences the vulnerability of the system to transmission distortions. In this paper, an address code which is assigned to each individual user was employed in order to reduce the collisions or hit. Also the frequency band is divided into several subbands and each user transmits multitone frequency per subband per chip. And the new system which is to increase the duration of each tone by increasing the total number of system frequencies that has been proposed. It is found that an optimum value bit, tone, number of frequencies per chirp can improve the err performance. This flexibility slightly increases maximum efficiecy and makes the the system less vulnerable to multipath delay. So, It is found that as the nuber of user increased 50%, the efficiency as a tuncion of the bandwidth to user'rate ratio improve 20%.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.11
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• pp.1598-1608
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• 2013

An optimum dietary carbohydrate content is important for maximum fish growth. In this study, we fed Wuchang bream (Megalobrama amblycephala) with either control diet (30.42%) or high carbohydrate diet (52.92%) for 90 d. Fish were fed to apparent satiation three times daily in an aquarium with automatic temperature control and circulated water. Growth performance, plasma biochemical parameters, hepatic morphology and enzyme activities were determined. It was shown that compared to fish fed control diet, fish fed high carbohydrate diet had higher plasma triglyceride and cortisol levels for d 90, and lower alkaline phosphatase level for d 45, lower hepatic superoxide dismutase and total antioxidative capacity for d 90, higher malondialdehyde for d 45 and glycogen content for d 45 and 90 (p<0.05). Histological and transmission electron microscopy studies showed that hepatocytes of fish fed high carbohydrate diet contained large lipid droplets, causing displacement of cellular organelles to periphery of hepatocytes. The relative level of hepatic heat shock protein 70 (HSP70) mRNA of Wuchang bream fed high carbohydrate diet was significantly higher than that of fish fed the control diet for 90 d (p<0.05). These changes led to decreased specific growth rate and increased feed conversion ratio (p<0.05). Upon hypoxia challenge, fish fed high carbohydrate diet had higher cumulative mortality than those fed the control diet (p<0.05). These results suggested that high dietary carbohydrate (52.92%) was detrimental to the growth performance and health of Wuchang bream.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4188-4206
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• 2016

Power control is widely used to reduce co-channel interference in wireless networks and guarantee the signal-to-interference plus noise ratio (SINR) of ongoing connections. This technique is also effective for wireless body area networks (WBANs). Although achieving satisfactory SINR is important for WBAN users, they may not be willing to achieve it at arbitrarily high power levels since power is a scarce resource in WBANs. Besides, for WBANs with different purposes, the QoS requirements and concern about the power consumption may be different. This motivates us to formulate the power control problem using the concepts from microeconomics and game theory. In this paper, the QoS objective is viewed as a utility function, which represents the degree of user satisfaction, while the power consumption is viewed as a cost function. The power control problem consequently becomes a non-cooperative multiplayer game, in which each player tries to maximize its net utility, i.e., the utility minus the cost. Within this framework, we investigate the Nash equilibrium existence and uniqueness in the game and derive the best response solution to reach the Nash equilibrium. To obtain the optimal transmission power in a distributed way, we further propose a utility-based and QoS-aware power control algorithm (UQoS-PCA). Tunable cost coefficient in UQoS-PCA enables this scheme to be flexible to satisfy diverse service requirements. Simulation results show the convergence and effectiveness of the proposed scheme as well as improvements over existing algorithm.

• Journal of Broadcast Engineering
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• v.16 no.6
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• pp.1026-1035
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• 2011

This paper presents generalization and application for the conventional SISO decoding algorithm of Block Turbo Codes. R. M. Pyndiah suggested an iterative SISO decoding algorithm for Product Codes, two-dimensionally combined linear block codes, on AWGN channel. It wascalled Block Turbo Codes. Based on decision of Chase algorithm which is SIHO decoding method, SISO decoder for BTC computes soft decision information and transfers the information to next decoder for iterative decoding. Block Turbo Codes show Shannon limit approaching performance with a little iteration at high code rate on AWGN channel. In this paper we generalize the conventional decoding algorithm of Block Turbo Codes, under BPSK modulation and AWGN channel transmission assumption, to the LLR value based algorithm and suggest an application example such as concatenated structure of LDPC codes and Block Turbo Codes.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.1080-1091
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• 2018

The eggshell, which is a complex and highly ordered structure, is very important factor for food safety and egg marketing. This study investigated the changes in eggshell structure and shell components in relationship to hen age. For this study, we examined the histological change of the endometrium of the 30-, 60-, and 72-wk-old commercial layers, and analyzed the ultrastructure and ionic composition of their eggshells. The results showed that histological deformation, fibrosis, atrophy and elimination of micro-villi in the uterus endometrium were found through microscopic observation that was associated with increasing hen age. Concentration of blood-ion components such as $Ca^{2+}$, $Na^+$, $K^+$, and $Cl^-$ ions did not change with age. Along with the results from the ultrastructure analysis of the eggshell, the palisade layer ratio and the density of mammillary knobs were significantly decreased in older hens. In addition, the type B mammillary knobs were frequently observed with increasing hen age. In the mineral element assay from the eggshell, $Ca^{2+}$, $S^{2-}$, and $Co^{2+}$ significantly decreased with increasing hen age, whereas $Na^+$, $K^+$, and $V^{2+}$ significantly increased. Therefore, the damages of endometrial tissue inhibit the processes of ion transmission and the crystallization of eggshell formation, resulting in a large and non-uniform mammillary knob formation. This means the conditions of endometrial cells affect the formation of the eggshell structure. In conclusion, hen aging causes the weakness of the eggshell and degrades the eggshell quality.

• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.127-132
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• 2010

Biomphalaria alexandrina snails play an indispensable role in transmission of schistosomiasis. Infection rates in field populations of snails are routinely determined by cercarial shedding neglecting prepatent snail infections, because of lack of a suitable method for diagnosis. The present study aimed at separation and quantification of oxalic, malic, acetic, pyruvic, and fumaric acids using ion-suppression reversed-phase high performance liquid chromatography (HPLC) to test the potentiality of these acids to be used as diagnostic and therapeutic biomarkers. The assay was done in both hemolymph and digestive gland-gonad complex (DGG) samples in a total of 300 B. alexandrina snails. All of the studied acids in both the hemolymph and tissue samples except for the fumaric acid in hemolymph appeared to be good diagnostic biomarkers as they provide not only a good discrimination between the infected snails from the control but also between the studied stages of infection from each other. The most sensitive discriminating acid was malic acid in hemolymph samples as it showed the highest F-ratio. Using the Z-score, malic acid was found to be a good potential therapeutic biomarker in the prepatency stage, oxalic acid and acetic acid in the stage of patency, and malic acid and acetic acid at 2 weeks after patency. Quantification of carboxylic acids, using HPLC strategy, was fast, easy, and accurate in prediction of infected and uninfected snails and possibly to detect the stage of infection. It seems also useful for detection of the most suitable acids to be used as drug targets.

• Parasites, Hosts and Diseases
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• v.58 no.3
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• pp.229-236
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• 2020

Cutaneous leishmaniosis (CL) is the most common form of leishmaniasis.CL caused by L. major and L. tropica is endemic in 17 provinces of Iran. This study was carried out to elucidate situation of CL in Ardabil province and to predict distribution of Phlebotomus papatasi and Phlebotomus sergenti (Diptera: Psychodidae) as vectors of CL in the region. In this cross-sectional study, data on CL patients were collected from local health centers of Ardabil province, Iran during 2006-2018 to establish a geodatabase using ArcGIS10.3. A total of 20 CL cases were selected randomly and skin samples were collected and analyzed by PCR method. MaxEnt 3.3.3 model was used to determine ecologically suitable niches for the main vectors. A total, 309 CL human cases were reported and the highest incidence rate of disease was occurred in Bilasavar (37/100,000) and Germi (35/100,000). A total of 2,794 sand flies were collected during May to October 2018. The environmentally suitable habitats for P. papatasi and P. sergenti were predicted to be present in northern and central areas of Ardabil province. The most variable that contributed ratio in the modeling were Isothermality and slope factors. Ardabil province is possibly an endemic are for CL. The presence of P. papatasi and P. sergenti justifies local transmission while the vectors of CL are existing in the northern and central areas of the province.

• Korean Journal of Materials Research
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• v.26 no.8
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• pp.430-437
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• 2016

Aluminum oxide ($Al_2O_3$) thin films were grown by atomic layer deposition (ALD) using a new Al metalorganic precursor, dimethyl aluminum sec-butoxide ($C_{12}H_{30}Al_2O_2$), and water vapor ($H_2O$) as the reactant at deposition temperatures ranging from 150 to $300^{\circ}C$. The ALD process showed typical self-limited film growth with precursor and reactant pulsing time at $250^{\circ}C$; the growth rate was 0.095 nm/cycle, with no incubation cycle. This is relatively lower and more controllable than the growth rate in the typical $ALD-Al_2O_3$ process, which uses trimethyl aluminum (TMA) and shows a growth rate of 0.11 nm/cycle. The as-deposited $ALD-Al_2O_3$ film was amorphous; X-ray diffraction and transmission electron microscopy confirmed that its amorphous state was maintained even after annealing at $1000^{\circ}C$. The refractive index of the $ALD-Al_2O_3$ films ranged from 1.45 to 1.67; these values were dependent on the deposition temperature. X-ray photoelectron spectroscopy showed that the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ were stoichiometric, with no carbon impurity. The step coverage of the $ALD-Al_2O_3$ film was perfect, at approximately 100%, at the dual trench structure, with an aspect ratio of approximately 6.3 (top opening size of 40 nm). With capacitance-voltage measurements of the $Al/ALD-Al_2O_3/p-Si$ structure, the dielectric constant of the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ was determined to be ~8.1, with a leakage current density on the order of $10^{-8}A/cm^2$ at 1 V.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.17.2-17.2
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• 2011

Double-walled carbon nanotubes (DWCNTs) were grown with vertical alignment on a Si wafer by using catalytic thermal chemical vapor deposition. This study investigated the effect of pre-annealing time of catalyst on the types of CNTs grown on the substrate. The catalyst layer is usually evolved into discretely distributed nanoparticles during the annealing and initial growth of CNTs. The 0.5-nm-thick Fe served as a catalyst, underneath which Al was coated as a catalyst support as well as a diffusion barrier on the Si substrate. Both the catalyst and support layers were coated by using thermal evaporation. CNTs were synthesized for 10 min by flowing 60 sccm of Ar and 60 sccm of H2 as a carrier gas and 20 sccm of C2H2 as a feedstock at 95 torr and $750^{\circ}C$. In this study, the catalyst and support layers were subject to annealing for 0~420 sec. As-grown CNTs were characterized by using field emission scanning electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy, and atomic force microscopy. The annealing for 90~300 sec caused the growth of DWCNTs as high as ~670 ${\mu}m$ for 10 min while below 90 sec and over 420 sec 300~830 ${\mu}m$-thick triple and multiwalled CNTs occurred, respectively. Several radial breathing mode (RBM) peaks in the Raman spectra were observed at the Raman shifts of 112~191 cm-1, implying the presence of DWCNTs, TWCNTs, MWCNTs with the tube diameters 3.4, 4.0, 6.5 nm, respectively. The maximum ratio of DWCNTs was observed to be ~85% at the annealing time of 180 sec. The Raman spectra of the as-grown DWCNTs showed low G/D peak intensity ratios, indicating their low defect concentrations. As increasing the annealing time, the catalyst layer seemed to be granulated, and then grown to particles with larger sizes but fewer numbers by Ostwald ripening.

• Journal of Korea Multimedia Society
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• v.8 no.7
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• pp.916-923
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• 2005

In recent times, mobile phones that play an important role in voice communication have became increasingly exciting due to the ability to transmit multimedia contents. However, user's communication cost and service usage fees for digital context exchange are still prohibitive. In this paper, we consider the task of transmitting a facial image in the context of mobile avatar generation. We present image compression as a useful technique to reduce service usage costs of data exchange in mobile communications. In view of this we propose an image compression algorithm that performs better than existing techniques. The suggested algorithm in this paper uses the location of significant coefficient on the wavelet image by detecting facial region as well as the spatial correlation between decomposed bands by wavelet transformation. The algorithm perform well and archives an efficient compression ratio. The proposed method recognizes location information of significant coefficient in advance, thus it is more suitable than existing general compression methods for mobile avatar generation systems.