• Journal of Chest Surgery
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• v.33 no.9
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• pp.738-743
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• 2000

Background: Video-assisted thoracic surgery(VATS) is being used as a therapeutic modality in many diseases in which thoracotomy has been used. We studied that the VATS can substitute the thoracotomy in benign esophageal disease. Material and Method: Group I (n=18) underwent video-assisted thoracic surgery, and group II(n=19) thoracotomy. Group I includes 14 leiomyomas and 4 achalasias. Group II includes 16 leiomyomas and 3 achalasias. Operative technique is enucleation in the leiomyoma and modified Heller's myotomy in the achalasia. Analyzing factors of operation-efficacy are anesthetic time, operation time, hospital stay, chest tube drainage amount and chest tube removal day. The degree of the postoperative pain is assessed by the frequency of opioid analgesics injection. Result: There was no death in both groups. There were 5 complications in the group I and 2 in the group II. Prolonged pleural effusion and restenosis of achalasia occurred to 1 patient in each group. In the group I, there were 1 temporaty vocal cord palsy and 2 mucosal tear leading to thoracotomy. There were no differences in anesthesia time, operation time, hospital stay, total chest tube drainage amount, chest tube removal day and frequency of opioid analgesics injection. The amount of the chest tube drainage at POD 1 day was significantly lower in group I(155.6$\pm$77.8cc) than in group II(572.8$\pm$280.1cc)(p<0.05). Conclusion: The results of our data showed that video-assisted thoracic surgery for benign esophageal disease is as effective as thoracotomy and in addition, cosmetic effect is much better. We concluded VATS may be a substitute for thoracotomy in benign esophageal disease.

• Journal of Chest Surgery
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• v.35 no.2
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• pp.166-169
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• 2002

Poststernotomy mediastinitis is a rare but potentially life-threatening complication of cardiac surgery. Up to present, poststernotomy wound infection has been treated by closure of wound directly or by use of myocutaneous flaps after irrigation and debridement of wound. We describe a new treatment of poststemotomy wound infection by using the vacuum-assisted closure technique. This technique was successfully applied in 3 patients with poststernotomy wound infection and mediastinitis, and a healed sternotomy wound could be achieved using this new technique.

• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.147-151
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• 2000

We deposited the ion assisted ${Ta_2}{O_5}$ films and conventional thermal evaporated ${Ta_2}{O_5}$ films by using electron beam gun, and measured the optical properties and mechanical properties of the fabricated films according to the evaporation conditions. In the case of the TazOs films by oxygen ion assisted deposition with the anode voltage of 120 V, and current density of $50~500\muA/cm^2$, the refractive index exhibited 2.15 which was higher than the conventionally deposited film index 1.94 and the tensile stress exhibited $5.0\times10^8 dyne/cm^2$ which was lower than $7.0\times10^8 dyne/cm^2$. This properties coincided with the optical and mechanical properties of the films deposited at the elevated substrate temperature of $230^{\circ}C$. In the case of the argon ion assisted films the tensile stress was decreased but the absorption existed at the short wavelength in the visible spectral region. And all the fabricated films were found to be amorphous by the X-ray diffraction analysis. lysis.

• Archives of Plastic Surgery
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• v.32 no.6
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• pp.727-732
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• 2005

The treatment of wounds of the lower extremity caused by diabetes or vascular dysfunction remains a difficult problem for the plastic surgeon. The use of negative pressure in wound healing is a relatively new method to facilitate chronic wound healing by secondary healing. The use of vacuum-assisted closure(VAC) system is purposed to reduce local edema, increase regional blood flow, enhance epithelial migration, preserve a moist wound environment, reduce bacterial colonization, promote granulation tissue formation, and mechanically enhance wound closure. The VAC also can be used as a dressing for anchoring an applied split thickness skin graft. We reviewed the data from 20 consecutive patients with non-healing wound in lower extremity at Dong-A University from March 2002 to December 2004. We used the VAC in 20 patients and compared the results with the control group. In the VAC using group, mean application duration was about 3 weeks and dressing change was done every other day. The follow-up period of patients ranged from 3 months to 30 months with a mean of 17 months. The points of comparison with control group are wound size, granulation tissue proliferation rate, operation method, preoperative time, postoperative healing time, complication, and cost. With those points, we propose to approve the efficiency of the VAC in non-healing wound. As a result, the VAC used in non-healing wound decrease wound size, accelerate granulation tissue formation, do a wound closure with less invasive operation method, make less postoperative complication, can make operation time shorter. Therefore it is cost effect. Our results demonstrate the usefulness of VAC as an adjunct in management of chronic wounds with other extrinsic factors.

• Korean Journal of Materials Research
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• v.16 no.2
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• pp.99-105
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• 2006

This paper reports an improved bonding method using the IPA (isopropyl alcohol) assisted low-temperature bonding process for the PMMA (polymethylmethacrylate) micro CE (capillary electrophoresis) chip. There is a problem about channel deformations during the conventional processes such as thermal bonding and solvent bonding methods. The bonding test using an IPA showed good results without channel deformations over 4 inch PMMA wafer at $60^{\circ}C$ and 1.3 bar for 10 minutes. The mechanism of IPA bonding was attributed to the formation of a small amount of vaporized acetone made from the oxidized IPA which allows to solvent bonding. To verify the usefulness of the IPA assisted low-temperature bonding process, the PMMA micro CE chip which had a $45{\mu}m$ channel height was fabricated by hot embossing process. A functional test of the fabricated CE chip was demonstrated by the separation of fluorescein and dichlorofluorescein. Any leakage of liquids was not observed during the test and the electropherogram result was successfully achieved. An IPA assisted low-temperature bonding process could be an easy and effective way to fabricate the PMMA micro CE chip and would help to increase the yield.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.139-145
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• 2005

In the study, in order to deposit TaN thin film using diffusion barrier and bottom electrode we made the Plasma Assisted ALD equipment and confirmed the electrical characteristic of TaN thin films deposited PAALD method, PAALD equipment depositing TaN thin film using PEMAT(pentakis(ethylmethlyamlno) tantalum) Precursor and $NH_3$ reaction gas is aware that TaN thin film deposited of high density and amorphous phase with XRD measurement The degree of diffusion and react ion taking place in Cu/TaN(deposited using 150 W PAALD)/$SiO_2$/Si systems with increasing annealing temperature was estimated from MOS capacitor property and the $SiO_2(600\;\AA)$/Si system surface analysis by C-V measurement and secondary ion material spectrometer(SIMS) after Cu/TaN/$SiO_2(400\;\AA)$ system etching. TaN thin film deposited PAALD method diffusion barrier have a good diffusion barrier property up to $500^{\circ}C$.

• The Journal of Korean Association of Computer Education
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• v.3 no.1
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• pp.31-41
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• 2000

Since the use of computer-mediated communication(CMC) systems has been steadily increasing in the teaching and learning environments, this study attempted to describe some of instructional strategies which can be employed as a medium of cooperative learning. One of the best way to conduct network-assisted instruction is to embed such a medium into cooperative learning. Network-assisted cooperative learning maximizes students' own learning and each other's learning using CMC, in which students can actively participate in their learning processes. The characteristics of CMC-transmission and search of information, interactivity, time and place independence-assist and enhance cooperative learning. In this study, the instructional strategies for cooperative learning via CMC are suggested as following: (1) choose the instructional goals, (2) structure positive interdependence, (3) select guidelines for grouping, (4) train cooperative skills to students, (5) set up the environments such as electronic bulletin-board, and (6) develop assessment tools. Finally, this study suggests that potentials of network-assisted cooperative learning can be realized by providing environments and thinking tools for cooperative learning. Appropriate theory and practice need to be followed up to support the cooperative learning systems.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.460-464
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• 2013

A series of Mn compound were prepared by seed-assisted method. The seed used in this reaction was manufactured by calcination of $MnCO_3$ at various temperatures and effects of the calcination temperature on seed-assisted reaction were investigated. With increase of the calcination temperature, CMD (${\gamma}-MnO_2$) was recovered after seed-assisted reactions. LMO used as cathode active material in the Li-ion batteries were synthesized from Mn source obtained in the seed-assisted reaction and the electrochemical properties (rate capability, cycle life performance and specific capacity) of the LMO were investigated. The LMO synthesized from the CMD which is obtained by the reaction with seed prepared by calcination of $MnCO_3$ more than $350^{\circ}C$ shown good electrochemical properties.

• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1501-1507
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• 2017

Telepresence in robot assisted learning has preferred low-height, shorter than life-size robotic platforms for reasons such as operational stability, user convenience and psychological comfort in human robot interaction. If, however, the reason for using a telepresence robot is to display the authority of a social superior to a social inferior, one can hypothesize that a robotic platform which reflects real-life height advantage would be better suited for the stated purpose than conventional low-height platforms. In order to test the hypothesis, we examined whether the height of the robot had an effect on an instructor connected to a telepresence robot in robot-assisted learning with regard to controlling a large number of elementary school students. The pre-and post experiment demonstrates that the use of a life-size telepresence robot, compared to a child-size telepresence robot, failed to make a meaningful difference in the instructors' authority being accepted by the students. However, behavioral measures shows that a taller robot has more merits in controlling students.

• ETRI Journal
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• v.37 no.5
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• pp.877-887
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• 2015

This paper is a first-hand summary on our comprehensive live trial of cellular-assisted device-to-device (D2D) communications currently being ratified by the standards community for next-generation mobile broadband networks. In our test implementation, we employ a full-featured 3GPP LTE network deployment and augment it with all necessary support to provide realtime D2D connectivity over emerging Wi-Fi-Direct (WFD) technology. As a result, our LTE-assisted WFD D2D system enjoys the required flexibility while meeting the existing standards in every feasible detail. Further, this paper provides an account on the extensive measurement campaign conducted with our implementation. The resulting real-world measurements from this campaign quantify the numerical effects of D2D functionality on the resultant system performance. Consequently, they shed light on the general applicability of LTE-assisted WFD solutions and associated operational ranges.