• Ocean Systems Engineering
• /
• v.9 no.4
• /
• pp.391-407
• /
• 2019

Tracking the location (position) of a surface or underwater marine vehicle is important as part of guidance and navigation. While the Global Positioning System (GPS) works well in an open sea environment but its use is limited whenever testing scaled-down models of such vehicles in the laboratory environment. This paper presents the design, development and implementation of a low energy ultrasonic augmented single beacon-based localization technique suitable for such requirements. The strategy consists of applying Extended Kalman Filter (EKF) to achieve location tracking from basic dynamic distance measurements of the moving model from a fixed beacon, while on-board motion sensor measures heading angle and velocity. Iterative application of the Extended Kalman Filter yields x and y co-ordinate positions of the moving model. Tests performed on a free-running ship model in a wave basin facility of dimension 30 m by 30 m by 3 m water depth validate the proposed model. The test results show quick convergence with an error of few centimeters in the estimated position of the ship model. The proposed technique has application in the real field scenario by replacing the ultrasonic sensor with industrial grade long range acoustic modem. As compared with the existing systems such as LBL, SBL, USBL and others localization techniques, the proposed technique can save deployment cost and also cut the cost on number of acoustic modems involved.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.26 no.1
• /
• pp.169-176
• /
• 2016

Android platform is designed to be user-friendly, yet sometimes its convenience introduces vulnerabilities that normal users cannot justify. In this paper, after making an overview of popular open source analysis tools for android applications, we point out the dangerous use of Permission Group in current Google Policy, and suggest a technique to mitigate the risks of privilege escalation that attackers are taking advantage of. By conducting the investigation of 21,064 malware samples, we conclude that the proposed technique is considered effective in detecting insecure application update, as well as giving users the heads-up in security awareness.

• Journal of Korean Academy of Nursing
• /
• v.28 no.3
• /
• pp.650-661
• /
• 1998

The purpose of this study was to provide fundamental data for determining contents of Fundamental Nursing Practice and developing desirable bedside nursing techniques for clinical nursing areas. Subjects for this study were 86 nurses who were employees of two university hospitals located in Seoul and a district area. Data were collected by questionnaires. Items of Fundamental Nursing Practice were classified into 72 items according to the result from content analysis of 9 textbooks of Fundamental Nursing. The results are as follows : 1) Items which above 80% of respondents practiced during the school inside practice or clinical nursing practice course were axillary temperature measurement, radial pulse measurement, respiratory rate measurement, application of oral hygiene, hand-washing technique, application of hot and cold bags, intramuscular injection technique, open bed-making, soap enema method, application of nelaton catheterization and oral and nasal suction methods. 2) Above 90% of respondents replied that all items except temperature measurement and bed-making were requisite contents for Fundamental Nursing Practice. Above 10% of respondents replied oral and rectal temperature measurement and bed-making were unnecessary content. 3) Above 90% of respondents replied that operating methods of all items except isolation technique, admission and discharge procedures, and retention enema in the Fundamental Nursing Practice course and clinical situation were consistent. The main reasons that respondents did not apply methods which they learned in the Fundamental Nursing Practice course to the clinical situation were 'insufficient time', 'colleagues were using different methods', 'insufficient supply of instuments' or 'inappropriate appliances'.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.51 no.11
• /
• pp.568-576
• /
• 2002

This paper presents a new algorithm for the enhancement of voltage stability by optimal routing (OR) technique. A new voltage stability index (VSI) for optimal routing is also proposed by using theories of critical transmission path based on voltage phasor approach and equivalent impedance method. Furthermore, the proposed algorithm automatically detect the critical transmission path to critical transmission path to critical load which are faced to voltage collapse due to additional real or reactive loading. We also adopt a improved branch exchange (IBE) algorithm based on a tie branch power (TBP) flow equation to apply the OR technique. The proposed IBE algorithm for the VSI maximizing can effectively search the optimal topological structures of distribution feeders by changing the open/closed states of the sectionalizing and tie switches. The proposed algorithm has been evaluated with the practical IEEE 32, 69 bus test systems and KEPCO 148 bus test system to show favorable performance.

• Journal of the Korean Vacuum Society
• /
• v.18 no.5
• /
• pp.390-393
• /
• 2009

We report on a new patterning technique for organic functional materials applicable to organic photovoltacis (OPVs). The unconventioal patterning technique, $O_2$ plsama-etching selectively perfluoro-alkyl fluorosilanes, is used for producing a bulk-heterojunction active layer with poly(3-hexylthiophene) as the electron donor and [6,6]-phenyl-$C_{61}$ butyric acid methyl ester as the electron acceptor. The patterning with reduced leakage path and parasitic capacitance suggests a way for fabrication of OPVs with higher energy conversion efficiency.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.31 no.2
• /
• pp.92-95
• /
• 2020

Tracheal granuloma, the most commonly reported sequela of pediatric tracheotomy. A variety of techniques are available for the management of tracheal granuloma. Potassium-titanyl-phosphate (KTP) laser has been previously established as an acceptable technique for removal of laryngeal surgery, which emits a green light with a wave length of 532 nm, which is well-absorbed by hemoglobin and can coagulate and vaporize tissue. The ability to deliver laser energy through a flexible glass fiber makes the technique convenient for use with a rigid bronchoscope, overcoming problems with intraluminal access encountered with earlier attempts at CO2 laser therapy for this problem. Another advantage of KTP laser is the avoidance of the risks and morbidity associated with an open procedure. We report our surgical technique KTP laser in the management of tracheal granuloma removal into the tracheostomy site. KTP laser is good tool for management of tracheal granuloma with low incidence of complications.

• International Journal of Computer Science & Network Security
• /
• v.22 no.10
• /
• pp.1-10
• /
• 2022

Nowadays software defect prediction (SDP) is most active research going on in software engineering. Early detection of defects lowers the cost of the software and also improves reliability. Machine learning techniques are widely used to create SDP models based on programming measures. The majority of defect prediction models in the literature have problems with class imbalance and high dimensionality. In this paper, we proposed Centroid and Nearest Neighbor based Class Imbalance Reduction (CNNCIR) technique that considers dataset distribution characteristics to generate symmetry between defective and non-defective records in imbalanced datasets. The proposed approach is compared with SMOTE (Synthetic Minority Oversampling Technique). The high-dimensionality problem is addressed using Ant Colony Optimization (ACO) technique by choosing relevant features. We used nine different classifiers to analyze six open-source software defect datasets from the PROMISE repository and seven performance measures are used to evaluate them. The results of the proposed CNNCIR method with ACO based feature selection reveals that it outperforms SMOTE in the majority of cases.

• Journal of Chest Surgery
• /
• v.56 no.1
• /
• pp.56-58
• /
• 2023

Untreated severe tricuspid regurgitation (TR) is associated with poor outcomes. Functional TR occurs secondary to dilatation of the annulus and tethering of the leaflets. Ring annuloplasty alone can correct most cases, but is insufficient in cases of severe annular dilatation due to severe leaflet tethering. In such cases, a tricuspid edge-to-edge technique may be an option. However, stitching of the leaflet tips alone is likely to result in tearing of the leaflets. Approximation of the durable chordae tendineae is considered helpful for this problem. Herein, we present the case of a 39-year-old man who had undergone open-heart surgery for acute type A aortic dissection 13 months earlier. A right mini-thoracotomy approach with a beating-heart strategy was used, which did not require unnecessary pericardial adhesiolysis and dissection. This technique had the advantage of reducing the operation time and the risk of bleeding. To summarize, we present a case of tricuspid valve repair in a high-risk patient with severe leaflet tethering that was successfully managed using these methods.

• Journal of Digestive Cancer Research
• /
• v.4 no.2
• /
• pp.113-121
• /
• 2016

Background: We evaluated technique of hepatic resections using suprahilar-extrafascial dissection of Glissonean pedicle with vascular stapling device for pedicle transection with intent to minimize operative time and blood loss. Methods: We analyzed the clinical records of 326 patients who underwent anatomic liver resection by suprahilar-extrafascial pedicle isolation with vascular stapling division technique. Results: The minor liver resections were associated with significantly shorter surgery duration (105.1±21.1 vs. 225.6±75.6) and transection time (40.1±14.5 vs. 96.3±55.2) than major hepatectomies (p<0.0001 for all). The mean blood loss was 350.8±100.5 mL in minor resection and 485.4±250.2 mL in major resection (p=0.001). The mean blood transfusion requirement was 400.8±109.5 mL for minor resections and 550.9±100.0 mL for major hepatectomy (p=0.072). There was no significant difference in morbidity and mortality between groups (p=0.980; p=0.945). Major as well as minor liver resection were oncology superior with no significant difference in the 5-year overall survival rates. Conclusion: Suprahilar-extrafascial dissection of Glissonean pedicle represents an effective and safe technique of liver resection. Presented approach allows early and easy ischemic delineation of appropriate liver territory to be removed with selective inflow vascular control. It is not time consuming and it is very useful in re-resection, as well as oncological reasonable.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.11
• /
• pp.17-23
• /
• 2004

The implementation and design of the wideband IFIU using aperture open loop resonator and reversed phase technique to reduce the local oscillator leakage signal was represented in this paper. The local oscillator leakage signal is generated in stage of frequency conversion, especially in frequency conversion of fully digital modulation signal close to DC signal. The leakage signal and spurious signals, which have effects on adjacent channel or in-band channel as interference signals, were reduced below -60 dBc for 45 Mbps and 155 Mbps IF interface units. The group delay for both IFIUs shows low ripple characteristics of 15 ns and 8 ns, respectively. Also, the amplitude ripple characteristic in 150 MHz bandwidth with L-band center frequency satisfies the required specification of 2 dB. The implemented IFIU provides the required specifications for wideband satellite communication system.