• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3A
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• pp.221-229
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• 2007

In this paper, we propose and analyze the optimized sleep mode for a mobile node (MN) in IEEE 802.16e wireless metropolitan area networks. Because a MN in a sleep mode specified in 802.16e specification should maintain state information with the base station currently attached, it must renew sleep state with a new base station after handover which leads to unnecessary waste of battery power. Noting that the mobility pattern of a MN is independent of call arrival patterns, we propose an optimized sleep mode to eliminate unnecessary standby period of a MN in sleep state after handover. We also propose an analytical model for the proposed scheme in terms of power consumption and the initial call response time. Simulation studies that compare the performance between the sleep mode and the optimized sleep mode show that our scheme marginally increases initial call response delay with the huge reduction in power consumption.

• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.87-91
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• 2006

With the growth of the internet, the number of wireless internet users has increased continuously up to date. However, mobile communications could not support high speed transmission rate with cheap communication fee and wireless LAN has problems in providing terminal mobility and wide area connectivity, respectively. So the WMAN standard has been newly designed to make up for these limits. The initial 802.16 specification effectively offers a solution for providing fixed users with high speed wireless communication but it does not offer terminal mobility. So the 802.16d and 802.16e have been developed as the next generation solution that can support various PHY layer (SC, SCa, OFDM, OFDMA) and offer the terminal mobility. In this paper, we propose an effective uplink scheduling algorithm for VoIP with using UGS, and we show that our proposed algorithm is superior in view of average delay and management of uplink bandwidth to conventional rtPS algorithm and the scheme in reference, with using NS-2 network simulator.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.240-248
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• 2002

$Fe_xTi_{l-x}O_2$ films (x=0.07 and 0.16) were grown by oxygen-plasma-assisted molecular beam epitaxy on rutile $TiO_2$(110). The same growth conditions were applied for both films in order to determine surface characteristics of grown films as a function of Fe composition. The films were characterized by several surface analysis techniques. The oxidation states of Ti and Fe in $Fe_xTi_{l-x}O_2$ films were found to be +4 and a mixture of +2 and +3, respectively. More $Fe^{3+}$ species exist in higher Fe doped film of $Fe_{0.16}Ti_{0.84}O_2$. The morphology of $Fe_{0.07}Ti_{0.93}O_2$ film shows tall rectangular and cylinderical islands growth on flat substrate-like surface. On the other hand, $Fe_{0.16}Ti_{0.84}O_2$ film consists of round shaped small islands showing somewhat rougher surface compared to the surface of $Fe_{0.16}Ti_{0.84}O_2$ film.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2011.10a
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• pp.16-16
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• 2011

Melanogenesis is a well-known physiological response of human skin that may occur because of exposure to ultraviolet light, for genetic reasons, or due to other causes. In our effectors to find new skin lightening agents, acanthoic acid (AA) was investigated for its ability to inhibit melanogenesis. The effects of AA isolated from A.koreanumun the expression of $\alpha$-MSH-induced melanogenic factors (tyrosinase, tyrosinase related protein (TRP)-1, TRP-2 and MITF (microphthalmla-associated transcriptional factor)) were investigated in murine B16F10 melanoma cells. The results indicate that AA was an effective inhibitor of melanogenesis in B16F10 cells. To elucidate the mechanism of the effect of AA on melanogenesis, we performed Western blotting for melanogenic proteins. AA inhibited melanogenic factors (tyrosinase, TRP-1, TRP-2) expressions. In this study, we also confirmed that AA decreased the protein level of MITF proteins, which would lead to a decrease of tyrosinase and related genes in B16F10 melanoma cells. In order to apply AA to the human skin, the cytotoxic effects of the AA were determined by MTT assays using human keratinocyte HaCaT cells. Based on these results, we suggest that AA be considered possible anti-melanogenic agent and might be effective against hyperpigmentation disorders for the topical application.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.579-583
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• 2015

This study was conducted on female patients with different gynecological problems attending the gynecology out-patient departments of two tertiary care hospitals in Peshawar city of Khyber Pakhtunkhwa, Pakistan between August 2012 and October 2013. The 200 patients had an age range of 21-65 years. Smears were taken with cervical brushes and preserved in preservative medium and processed for manual liquid based cytology (MLBC) for Pap staining. Out of 200 collected samples, 30 samples were found inadequate on cytology. Of the remaining 170 samples, 164 (96.47%) were normal, 5 (2.94%) were of atypical squamous cells of unknown significance (ASCUS) and 1 (0.6%) was of high grade squamous intraepithelial lesion (HSIL). On PCR all the samples were positive for beta globin gene fragment including those reported inadequate on cytology. Out of the 5 ASCUS samples, 2 samples were positive for HPV, one each for HPV 16 and HPV 18, and the rest of the 3 samples were negative for HPV DNA. The 1 sample of HSIL was positive for HPV 16 on PCR. Out of 164 normal samples on cytology, only 1 sample was HPV 16 positive. So overall, 4 (2%) out of 200 samples were positive for HPV DNA, where 3 were HPV 16 (1.5%), and 1 was HPV 18 (0.5%) positive, and thus the ratio of infection with of HPV 16 to HPV 18 was 3:1 in the general population. In conclusion, PCR based HPV detection is a more sensitive method for screening of HPV infection than cytology as sample inadequacy does not affect the results. However, it can be combined with cytology methods in a HPV positive female to achieve the maximum results.

• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.9-14
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• 1991

In order to investigate electronic and magnetic properties of $Fe_{16}N_{2}$ ferromagnet, we have performed electronic structure calculations employing the self-consistent local density functional LMTO(linearized muffin tin orbital) band method. We have obtained the ground state parameters, such as band structures, density of states, Stoner parameters, and magnetic moments. Based on these results, we have investigated microscopically the magnetic structure and the enhancement of Fe magnetic moments in this compound. Magnetic moments of 3 types of Fe(Fe I, Fe II and Fe III) in $Fe_{16}N_{2}$ are 2.13, 2.50, and $2.85\;{\mu}_{B}$, respectively. Large enhancement of Fe magnetic moment is observed in Fe II and Fe III, which are located rather far from N. This implies that local environment is very important in determining the Fe magnetic moments in this compound. Our value of average magnetic moment per Fe atom. $2.50\;{\mu}_{B}$, is a bit smaller than the reported estimate, $-3.0\;{\mu}_{B}$, from the experiment.

• Tuberculosis and Respiratory Diseases
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• v.70 no.6
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• pp.504-510
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• 2011

Background: $^{67}Ga$ scintigraphy has been used for years in sarcoidosis for diagnosis and to determine the extent of the disease. The present report is a study of various findings of $^{67}Ga$ scintigraphy in patients with sarcoidosis. Methods: Between 1998 and 2007, 16 patients (male：female, 6:10; age, $35.9{\pm}15.3$ years) with histologically proven sarcoidosis underwent clinical evaluation and $^{67}Ga$ scintigraphy. According to the site of involvement, they were divided into subtypes and analyzed. Results: Sixteen patients with sarcoidosis had involvement of various organs, including lymph nodes (13/16, 81.3%), lung (3/16, 18.8%), muscle (1/16, 6.3%), subcutaneous tissue (1/16, 6.3%), glands (1/16, 6.3%), and bone (1/16, 6.3%). Sites of involved lymph nodes were thorax (12/13, 92.3%), supraclavicular area (5/13, 38.5%), inguinal area (2/13, 15.4%), abdomen (2/13, 15.4%), and pelvis (1/13, 7.7%). Conclusion: Because sarcoidosis frequently involves multiple organs, $^{67}Ga$ scintigraphy is a useful method in for evaluating the whole body. Nuclear medicine physicians should be familiar with the various findings of gallium uptake in sarcoidosis.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.97-102
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• 2010

In this paper, an area-efficient FFT processor is proposed for IEEE 802.16e mobile WiMax systems. The proposed scalable FFT processor can support the variable length of 128, 512, 1024 and 2048. By reducing the required number of non-trivial multipliers with mixed-radix (MR) and multi-path delay commutator (MDC) architecture, the complexity of the proposed FFT processor is dramatically decreased without sacrificing system throughput. The proposed FFT processor was designed in hardware description language (HDL) and synthesized to gate-level circuits using 0.18um CMOS standard cell library. With the proposed architecture, the gate count for the processor is 46K and the size of memory is 64Kbits, which are reduced by 16% and 27%, respectively, compared with those of the 4-channel radix-2 MDC (R2MDC) FFT processor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12C
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• pp.1143-1149
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• 2006

In this paper, the modified iterative decoding algorithm[8] by partitioning check nodes is applied to low-density parity-check(LDPC) codes in IEEE 802.16e standards, which gives us the improvement for convergence speed of decoding. Also, the new method of check node partitioning which is suitable for decoding of the LDPC codes in IEEE 802.16e system is proposed. The improvement of convergence speed in decoding reduces the number of iterations and thus the computational complexity of the decoder. The decoding method by partitioning check nodes can be applied to the LDPC codes whose decoder cannot be implemented in the fully parallel processing as an efficient sequential processing method. The modified iterative decoding method of LDPC codes using the proposed check node partitioning method can be used to implement the practical decoder in the wireless communication systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.319-328
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• 2009

IEEE 802.16e standard defines different Sleep Mode Operations according to kind of services which aims at saving energy for MS efficiently. The previous study of Sleep Mode Operation is limited for single service environment, real sleep interval is decreased because different Sleep Mode Operations are applied at once when MS is on multi service. The proposed Enhanced Sleep Mode Operation increasing real sleep interval of this paper guarantees QoS(Quality of Services) which is same as standard, minimizes energy consumption when different Sleep Mode Operations are applied at once. Therefore Enhanced Sleep Mode Operation of this paper will be useful in case of increase battery life time as well as guaranteeing QoS for MS in IEEE 802.16 system.