• Journal of Electrochemical Science and Technology
• /
• v.12 no.4
• /
• pp.387-397
• /
• 2021

Deep eutectic solvents have been established as feasible metal electroplating solvent alternatives over traditional toxic aqueous plating baths. However, water, either added intentionally or unintentionally, can significantly influence the solvent's physical properties and performance, thereby hindering its industry application. In this study, the hygroscopicity, or the ability to absorb moisture from the environment, of synthesized ethaline (1:2 choline chloride:ethylene glycol) was investigated. The kinematic viscosity, electrical conductivity, electrochemical window, and water content of ethaline were monitored over a 2-week period. Karl Fischer titration tests showed that ethaline exposed to the atmosphere displayed significant hygroscopicity compared to its unexposed counterpart. ¹H NMR spectroscopy revealed that water vapor was readily absorbed at the surface due to the hydrophilic groups present in the ethaline molecule. Water uptake resulted in the decrease in viscosity, increase in electrical conductivity and narrowing of the electrochemical window of ethaline. Solution heating at 100℃ removed the absorbed moisture and allowed the recovery of the solvent's initial properties.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.6
• /
• pp.307-315
• /
• 2010

Although a substantial amount of studies have been carried out in order to improve the performance of IEEE 802.11, most of them focused on how to slowly decrease the Contention Window size, instead of resetting it to its initial value. Slow decreasing of the window size reduces the collision probability and increases the channel throughput. Therefore, it is difficult to achieve good results in a heterogeneous network which coexists with the original DCF. For instance, a Gentle DCF(GDCF) has good performance in a homogeneous environment, while it can hardly transmit frames in a heterogeneous environment including the original DCF. It is because the slow decreasing of the window size reduces the transmission probability. In this paper, we propose a Fast Recovery DCF(FRDCF) to solve this problem. In the FRDCF, the reset mechanism of the original DCF is maintained to keep the transmission probability high, while a new counter is used to enhance the performance of the wireless LAN. We prove that, compared with the GDCF, the FRDCF has better performance in a heterogeneous wireless LAN.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.32 no.5
• /
• pp.442-446
• /
• 2010

Purpose: The purpose of this study was to compare the clinical efficacy of popular bone graft materials mineralized allograft and deproteinized bovine bone mineral. Materials and Methods: One hundred seven implants of 78 patients, accompanied by sinus lift using the lateral window technique and simultaneous implantation, were sampled. In addition, some patients with severe systemic conditions were excluded. The initial bone heights of all patients ranged from 3-6 mm. All of the sample cases were treated at our hospital from January 2005 to January 2008. Techniques other than the lateral window technique were excluded, and only one graft material ($Tutoplast^{(R)}$ or Bio-$Oss^{(R)}$) was accepted for inclusion. $Tutoplast^{(R)}$ was used in 63 implants of 41 patients, whereas Bio-$Oss^{(R)}$) was chosen for the remaining 44 implants of 37 patients. The diameters of the particles used ranged from 0.25-1.0 mm, and the volume was 0.5-2 cc (mean, 1.5 cc). Results: The survival rate of the implant fixtures was 99.07% when the lateral window technique was used. Among all of the cases, cases in which $Tutoplast^{(R)}$ was used demonstrated a survival rate of 98.4%, whereas Bio-$Oss^{(R)}$) resulted in 100% survival. With respect to the alveolar bone height, no significant differences were detected between the two graft materials that failed. Conclusion: According to the result reported above, the two common materials for sinus augmentation do not have clinically significant difference. Rather, host factors, such as the height of residual bone, which could be disclosed during questioning patients' systemic conditions, might have greater effects on the prognosis.

• The KIPS Transactions:PartB
• /
• v.17B no.5
• /
• pp.389-398
• /
• 2010

The Vehicle Routing and Scheduling Problem with Time Windows(VRSPTW) is to establish a delivery route of minimum cost satisfying the time constraints and capacity demands of many customers. The VRSPTW takes a long time to generate a solution because this is a NP-hard problem. To generate the nearest optimal solution within a reasonable time, we propose the heuristic by using an ACO(Ant Colony Optimization) with multi-cost functions. The multi-cost functions can generate a feasible initial-route by applying various weight values, such as distance, demand, angle and time window, to the cost factors when each ant evaluates the cost to move to the next customer node. Our experimental results show that our heuristic can generate the nearest optimal solution more efficiently than Solomon I1 heuristic or Hybrid heuristic applied by the opportunity time.

• Journal of Korean Neurosurgical Society
• /
• v.50 no.1
• /
• pp.1-5
• /
• 2011

Objective : There is no proven regimen to reduce the severity of stroke in patients with acute cerebral infarction presenting beyond the thrombolytic time window. Ozagrel sodium, a selective thromboxane A2 synthetase inhibitor, has been known to suppress the development of infarction. The antiplatelet effect is improved when aspirin is used together with a thromboxane synthetase inhibitor. Methods : Patients with non-cardiogenic acute ischemic stroke who were not eligible for thrombolysis were randomly assigned to two groups; one group received ozagrel sodium plus 100 mg of aspirin (group 1, n=43) and the other 100 mg of aspirin alone (group 2, n=43). Demographic data, cardiovascular risk factors, initial stroke severity [National Institute of Health Stroke Scale (NIHSS) and motor strength scale] and stroke subtypes were analyzed in each group. Clinical outcomes were analyzed by NIHSS and motor strength scale at 14 days after the onset of stroke. Results : There were no significant differences in the mean age, gender proportion, the prevalence of cardiovascular risk factors, stroke subtypes, and baseline neurological severity between the two groups. However, the clinical outcome for group 1 was much better at 14 days after the onset of stroke compared to group 2 (NIHSS score, p=0.007, Motor strength scale score, p<0.001). There was one case of hemorrhagic transformation in group 1, but there was no statistically significant difference in bleeding tendency between two groups. Conclusion : In this preliminary study, thromboxane A2 synthetase inhibitor plus a low dose of aspirin seems to be safe and has a favorable outcome compared to aspirin alone in patients with acute ischemic stroke who presented beyond the thrombolytic time window.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.3
• /
• pp.407-415
• /
• 2012

In this paper, we propose a new stereo matching algorithm by using color information especially for stereo images containing human beings in the applications such as tele-presence system. In the proposed algorithm, we first remove the background regions by using a threshold value for stereo images obtained by stereo camera and then find an initial disparity map and segment a given image into R, G, B and white color components. We also obtain edges in the segmented image and estimate the disparity from the extract boundary regions. Finally, we generate the final disparity map by properly combining the disparity map of each color component. Experiment results show better performance compared with the window based method and the dynamic programing method especially for stereo images with human being.

• Journal of Broadcast Engineering
• /
• v.12 no.3
• /
• pp.278-288
• /
• 2007

We propose the fast full search algorithm that reduces the computational load of the block matching algorithm which is used for a motion estimation in the video coding. Since the conventional spiral search method starts searching at the center of the search window and then moves search point to estimate the motion vector pixel by pixel, it is good for the slow motion picture. However we proposed the efficient motion estimation method which is good for the fast and slow motion picture. Firstly, when finding the initial threshold value, we use the expanded predictor that can approximately calculate minimum threshold value. The proposed algorithm estimates the motion in the new search order after partitioning the search window and adapt the directional search order in the re-divided search window. At the result, we can check that the proposed algorithm reduces the computational load 94% in average compared to the conventional spiral full search algorithm without any loss of image quality.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.5A
• /
• pp.267-275
• /
• 2003

In UMTS terminal modem uses 3 step search procedure for initial cell search, which comprises 1) slot synchronization, 2) code group identification and frame synchronization, and 3) scrambling-code identification. The performance of initial cell search procedure depends on search parameters like observation time and threshold. The purpose of this paper is to get the optimal observation time and threshold of each step for minimum mean acquisition time. In this paper we induce mean detection time of each step and mean acquisition timefrom the model of 3 step search procedure using state diagram. Also we propose initial cell search algorithm which utilize window search method against initial oscillator error, and select an appropriate observation time and threshold of each step by the analysis of simulation and induced result. It is shown that the mean acquisition time in multipath fading channel can be shorter than 500ms by using the determined observation time and threshold of each step.

• The Journal of the Korean bone and joint tumor society
• /
• v.10 no.2
• /
• pp.71-78
• /
• 2004

Purpose: The purpose of this study is to investigate the characteristic of recurred giant cell tumor after bony curettage and cementation, and to review a way to prevent the recurrence. Materials and Methods : Thirty seven cases were analyzed, which were pathologically diagnosed giant cell tumor after diagnostic biopsy or surgical excision, followed by curative curettage, burring and cementation. Location, character, and time interval to recurrence were reviewed. Results: Thirteen out of thirty seven analyzed cases(35%) showed recurrence after primary curettage and cementation. The mean interval to recurrence was sixteen months(5 months to 43 months). Most of recurrence happened within the first two years except two cases. Among the recurred cases, eleven showed recurrence in the vicinity of window area. Two cases recurred in the depth of bone marrow, where cementation was made. The advantage of curettage and cementation is the immediate stability of the operation site, early rehabilitation, and early detection of recurrence. Furthermore, cementation is beneficial in that the cement-producing heat can eradicate the residual tumor burden. In this study, 85% of cases with insufficient curettage (for example, in cases where too small surgical window was made, or where there were anatomical difficulty in approaching the target tumor burden) showed recurrence. Conclusion: Bony curettage, burring and cementation is widely used as the primary curative modality for giant cell tumor. A few other modalities such as chemical cautery using phenol and $H_2O_2$; cryotherapy; and anhydroalcohol have also been introduced, but the benefit of these are still questionable. For some cases that relatively small surgical window was made due to anatomically complicated structures (such as ligament insertion or origin site) over the target tumor burden, unsatisfactory curettage and burring was made. This study showed high chance of recurrence after unsatisfactory curettage, and 85% of recurrence developed in the vicinity of the small window area. Most of the recurrence occurred within the first two years. It is concluded that sufficient window opening, extensive curettage and eradicative burring are key factors to prevent recurrence. Also, it should be reminded that careful and close observation should be made for at least the first two years after initial treatment for early detection of recurrence.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1996.04a
• /
• pp.282-282
• /
• 1996

The purpose of this study was to prepare the nifedipine dry elixir (NDE) and coated nifedipine dry elixir (CNDE) containing nifedipine ethanol solution for improving the dissolution rate and bioavailability of nifedipine. NDE containing nifedipine and ethanol in wall materials of dextrin was prepared using a spray-dryer and then NDE was coated with eudragit acrylic resin to make CNDE. Shape and size of the NDE and CNDE were monitored by scanning electron micrograph and laser particle size analyzer In vitro dissolution tests were performed in simulated gastric and intestinal fluid. Bioavailability of NDE and CNDE were compared with drug powder suspension and commercial soft capsule after oral administration of the preparations to rats. NDE and CNDE are spherical in shape. Cross-sectional view of dry elixirs indicates the large inter cavity containing ethanolic drug solution in shell. Geometric mean diameter of NDE and CNDE is about 6.64 and 8.70 $\mu\textrm{m}$, respectively. Drug dissolution rate within first 5 min from NDE increased dramatically irrespective of dissolution medium. However, CNDE showed a particularly retarded dissolution rate in pH 1.2 simulated gastric fluid compared with NDE. The bioavailability of nifedipine in the NDE was increased dramatically compared with drug powder suspension. CNDE reduced initial burst-out plasma peak compared with NDE. CNDE as a sustained release delivery system could reduce the initial burst-out plasma peak due to controlling the release rate of nifedipine from NDE and maintain the effective plasma level over a longer period within therapeutic window with enhanced bioavailability of nifedipine.