• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.814-827
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• 2004

The compressed mode is used to perform inter-frequency and inter-system handover in WCDMA. The instantaneous transmit power is increased in the compressed frame in order to keep the QoS(Quality of Service) unaffected by the reduced processing gain. Furthermore, since the inner loop power control is not active during the transmission gap and the effect of interleaving is decreased, a higher Eb/No target is required, which directly affects the system performance. Due to the impact on performance, the compressed mode should be activated by the RNC(Radio Network Controller) only when there is real need to execute an inter-frequency or inter-system handover. However, 3GPP does not define the method that decides the compressed mode activation. In order to reduce performance degradation, there is need the decision method. In this paper, we consider a combined cell structure in which some neighbor cells have a frequency the same as serving cell and the others have a different frequency or system. Under consideration, we analyze the effect of the compressed mode on the WCDMA forward link performance. In order to avoid performance degradation, we propose an UE(User Equipment) measurement method that can restrict the activation area of the compressed mode of UE that does not need it and evaluate its performance by simulations. Analytical results show that the use of the compressed mode affects the performance degradation. And simulation results show that proposed method leads to better performance.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.583-590
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• 2020

Deinococcus actinosclerus BM2^T (GenBank: KT448814) is a radio-resistant bacterium that is newly isolated from the soil of a rocky hillside in Seoul. As an extremophile, D. actinosclerus BM2^T may possess anti-inflammatory properties that may be beneficial to human health. In this study, we evaluated the anti-inflammatory effects of BM2U, an aqueous extract of D. actinosclerus BM2^T, on lipopolysaccharide (LPS)-mediated inflammatory responses in RAW264.7 macrophage cells. BM2U showed antioxidant capacity, as determined by the DPPH radical scavenging (IC₅₀ = 349.3 ㎍/ml) and ORAC (IC₅₀ = 50.24 ㎍/ml) assays. At 20 ㎍/ml, BM2U induced a significant increase in heme oxygenase-1 (HO-1) expression (p < 0.05). BM2U treatment (0.2-20 ㎍/ml) significantly suppressed LPS-induced increase in the mRNA expression of proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 (p < 0.05). BM2U treatment also suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), which are involved in the production of inflammatory mediators. BM2U treatment also inhibited the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs): JNK, ERK, and p-38 (p < 0.05). Collectively, BM2U exhibited anti-inflammatory potential that can be exploited in attenuating inflammatory responses.

• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.348-357
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• 2007

One of the major issues in recent researches on wireless sensor networks is to reduce energy consumption of sensor nodes operating with limited battery power, in order to lengthen their lifespan. Among the researches, we are interested in the schemes in which a sensor node periodically turns on and off its radio and requires information on the time when its neighbors will wake up (or turn on). Clock synchronization is essential for wakeup scheduling in such schemes. This paper proposes three methods based on the asynchronous averaging algorithm for clock synchronization in sensor nodes which periodically wake up: (1) a fast clock synchronization method during an initial network construction period, (2) a periodic clock synchronization method for saving energy consumption, and (3) a decision method for switching the operation mode of sensor nodes between the two clock synchronization methods. Through simulation, we analyze maximum clock difference and the number of messages required for clock synchronization.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.192-195
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• 2012

We reported diborane ($B_2H_6$) doped wide bandgap hydrogenated amorphous silicon oxide (p-type a-SiOx:H) films prepared by using silane ($SiH_4$) hydrogen ($H_2$) and nitrous oxide ($N_2O$) in a radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD) system. We improved the $E_{opt}$ and conductivity of p-type a-SiOx:H films with various $N_2O$ and $B_2H_6$ ratios and applied those films in regards to the a-Si thin film solar cells. For the single layer p-type a-SiOx:H films, we achieved an optical band gap energy ($E_{opt}$) of 1.91 and 1.99 eV, electrical conductivity of approximately $10^{-7}$ S/cm and activation energy ($E_a$) of 0.57 to 0.52 eV with various $N_2O$ and $B_2H_6$ ratios. We applied those films for the a-Si thin film solar cell and the current-voltage characteristics are as given as: $V_{oc}$ = 853 and 842 mV, $J_{sc}$ = 13.87 and 15.13 $mA/cm^2$. FF = 0.645 and 0.656 and ${\eta}$ = 7.54 and 8.36% with $B_2H_6$ ratios of 0.5 and 1% respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.12
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• pp.1085-1092
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• 2012

Mobile communication systems define user state transition mechanisms in order to manage radio resources and battery power efficiently. In the state transition mechanism, a state with a higher energy consumption inherently offers a shorter access delay, so there is a tradeoff between the energy and delay performances. In this paper, we analyze the user state transition mechanism of UMTS by considering the bursty traffic attributes of mobile applications. We perform a numerical evaluation for both the energy consumption and the activation delay by Markov modeling of the state transition mechanism, and investigate their tradeoff relationship as functions of operational parameters. The resulting energy-delay tradeoff curves clearly show an achievable performance bound of the user state transition mechanism and also offer an optimal operation strategy to minimize the energy consumption while guaranteeing the delay requirement.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.5
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• pp.413-422
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• 2020

Delphinidin is a major anthocyanidin compound found in various vegetables and fruits. It has anti-oxidant, anti-inflammatory, and various other biological activities. In this study we demonstrated the anti-cancer activity of delphinidin, which was related to autophagy, in radiation-exposed non-small cell lung cancer (NSCLC). Radiosensitising effects were assessed in vitro by treating cells with a subcytotoxic dose of delphinidin (5 μM) before exposure to γ-ionising radiation (IR). We found that treatment with delphinidin or IR induced NSCLC cell death in vitro; however the combination of delphinidin pre-treatment and IR was more effective than either agent alone, yielding a radiation enhancement ratio of 1.54 at the 50% lethal dose. Moreover, combined treatment with delphinidin and IR, enhanced apoptotic cell death, suppressed the mTOR pathway, and activated the JNK/MAPK pathway. Delphinidin inhibited the phosphorylation of PI3K, AKT, and mTOR, and increased the expression of autophagy-induced cell death associated-protein in radiation-exposed NSCLC cells. In addition, JNK phosphorylation was upregulated by delphinidin pre-treatment in radiation-exposed NSCLC cells. Collectively, these results show that delphinidin acts as a radiation-sensitizing agent through autophagy induction and JNK/MAPK pathway activation, thus enhancing apoptotic cell death in NSCLC cells.

• Journal of radiological science and technology
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• v.43 no.5
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• pp.389-395
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• 2020

The evaluation of radioactivated components of heavy-ion accelerator facilities affects the safety of radiation management and the exposure dose for workers. and this is an important issue when predicting the disposal cost of waste during maintenance and dismantling of accelerator facilities. In this study, the FLUKA code was used to simulate the proton treatment device nozzle and classify the radio-nuclides and total radioactivity generated by each component over a short period of time. The source term was evaluated using NIST reference beam data, and the neutron flux generated for each component was calculated using the evaluated beam data. Radioactive isotopes caused by generated neutrons were compared and evaluated using nuclide information from the International Radiation Protection Association and the Korea Radioisotope association. Most of the nuclides produced form of beta rays and electron capture, and short-lived nuclides dominated. However, In the case of ⁵⁴Mn, which is a radioactive product of iron, the effect of gamma rays should be considered. In the case of tritium generated from a material with a low atomic number, it is considered that handling care should be taken due to its long half-life.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.158-161
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• 2003

To develop an effective adsorbent for radio active Carbon Dioxide, $^14CO_2$, which is discharged to nearby atmosphere from nuclear power plants of CANDU type, we made some preliminary adsorbents and tested their abilities of $CO_2$ removal. The chemical agents used was LiOH and we supported or impregnated it on the surface or the internal volume of activated Carbon(GW-H). The physical and chemical properties of various adsorbents were measured using methods such as XRD, BET. SEM images were taken to investigate the change of surface morphology of the adsorbents. Finally, amount of $CO_2$ adsorption of them were verified under specific conditions. We found that mechanical mixing of LiOH and activated Carbon showed the maximum $CO_2$ removal ability, while surface activation of activated Carbon by Nitric Acid-treatment enhanced its $CO_2$ removal efficiency to some degree.

• Korean Journal of Materials Research
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• v.19 no.4
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• pp.203-206
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• 2009

$Sn_XSe_{100-X}$ (15|X|30) alloys have been studied to explore their suitability as phase change materials for nonvolatile memory applications. The phase change characteristics of thin films prepared by a Radio Frequency (RF) magnetron co-sputtering system were analyzed by an X-ray diffractometer and 4-point probe measurement. A phase change static tester was also used to determine their crystallization under the pulsed laser irradiation. X-ray diffraction measurements show that the transition in sheet resistance is accompanied by crystallization. The amorphous state showed sheet resistances five orders of magnitude higher than that of the crystalline state in $Sn_XSe_{100-X}$ (x = 15, 20, 25, 30) films. In the optimum composition, the minimum time of $Sn_XSe_{100-X}$ alloys for crystallization was 160, 140, 150, and 30ns at 15mW, respectively. The crystallization temperature and the minimum time for crystallization of thin films were increased by increasing the amount of Sn, which is correlated with the activation energy for crystallization.

• Journal of Pharmaceutical Investigation
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• v.4 no.4
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• pp.17-25
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• 1974

1. Neutron acivation analysis of arsenic contained in Korean human liver was studied in the view point of forensic chemistry, using 12 corpses. A sample of 1g was irradiated for 30 mins. in a neutron flux of $1.2{\times}10^{12}n/cm^2/sec$, followed by nitric-sulfuric acid digestion and then by Gutzeit separation. Radio activity was detected by it's scintillation counter. The arsenic content in the liver was found to be $0.01{\mu}g/g$ to $0.15{\mu}g/g$. 2. A rapid and convenient method for the radiochemical determination of minerals by neutron activation analysis was established. After neutron irradiation to the standard soln. of Cu and Mn in pneumatic tube (neutron flux : $1.2{\times}10^{12}n/cm^2/sec$), Cu and Mn were determined by estimating the ratio of the widths under energy peak area in ${\gamma}-ray-spectrogram$. When the standard soln. of Mn and Cu is irradiated for 15 mins. to 18 hrs., recovery test shows that the relative errors are 5.1% and 4.5% for copper and manganese, respectively.