• Journal of the Korea Institute of Military Science and Technology
• /
• v.25 no.4
• /
• pp.381-389
• /
• 2022

Detecting partially occluded objects is difficult due to the appearances and shapes of occluders are highly variable. These variabilities lead to challenges of localizing accurate bounding box or classifying objects with visible object parts. To address these problems, we propose a two-stage part-based attention approach for robust object detection under partial occlusion. First, our part attention network(PAN) captures the important object parts and then it is used to generate weighted object features. Based on the weighted features, the re-weighted object features are produced by our reinforced PAN(RPAN). Experiments are performed on our collected military vehicle dataset and synthetic occlusion dataset. Our method outperforms the baselines and demonstrates the robustness of detecting objects under partial occlusion.

• Clinical and Experimental Otorhinolaryngology
• /
• v.11 no.4
• /
• pp.233-241
• /
• 2018

Objectives. As endoscopic instrumentation, techniques and knowledges have significantly improved recently, endoscopic ear surgery has become increasingly popular. Transcanal endoscopic ear surgery (TEES) can provide better visualization of hidden areas in the middle ear cavity during congenital cholesteatoma removal. We aimed to describe outcomes for TEES for congenital cholesteatoma in a pediatric population. Methods. Twenty-five children (age, 17 months to 9 years) with congenital cholesteatoma confined to the middle ear underwent TEES by an experienced surgeon; 13 children had been classified as Potsic stage I, seven as stage II, and five as stage III. The mean follow-up period was 24 months. Recurrence of congenital cholesteatoma and surgical complication was observed. Results. Congenital cholesteatoma can be removed successfully via transcanal endoscopic approach in all patients, and no surgical complications occurred; only one patient with a stage II cholesteatoma showed recurrence during the follow-up visit, and the patient underwent revision surgery. The other patients underwent one-stage operations and showed no cholesteatoma recurrence at their last visits. Two patients underwent second-stage ossicular reconstruction. Conclusion. Although the follow-up period and number of patients were limited, pediatric congenital cholesteatoma limited to the middle ear cavity could be safely and effectively removed using TEES.

• Journal of Chest Surgery
• /
• v.32 no.11
• /
• pp.1009-1016
• /
• 1999

Background: Minimally invasive direct coronary artery bypass surgery(MIDCAB) has been increasing in interest along with the new techniques in myocardial immobilization for easier and safer procedures. Until the opening of the era of new techniques, adequate accuracy and good patency of grafts were debatable. Our experiences of MIDCAB were studied according to the stages of technical developments. Material and Methods: Since March 1996, 55 patients have undergone MIDCAB procedures. The patients of off-pump CABG(no cardiopulmonary bypass under full sternotomy) were excluded from the study. In the early experience(Stage I), a left anterior small thoracotomy through the left parasternal incision was performed(n=6); then an approach through the lower partial sternotomy was used(Stage II, n=33); and recently, a chest wall elevator for harvesting the internal thoracic artery and the foot plate for myocardial immobilization have been used(USSC, Norwalk, CT)(Stage III, n=16). Result: The surgical procedures of four patients in the Stage II group have been converted to conventional bypass because of the deeply seated left anterior descending coronary artery in two patients, fracture of the calcific lesion in the right coronary artery in one patient, and a cardiogenic shock during hypothermia in the other patient with ventricular dysfunction. Two patients in stage II experienced symptomatic recurrences after surgery and restenosis was verified on angiocardiography. They were managed by interventional procedures. All the other patients were doing well without symptoms, except one patients in Stage II who underwent PTCA procedure for a lesion in the circumflex artery during the follow up period. Conclusion: The new and specialized devices are essential to the development of MIDCAB surgery. MIDCAB and the hybrid procedures in multi-vessel disease are on the way to further development. So far, our experience is limited only to a single device among the many new devices for the purpose.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.12
• /
• pp.643-650
• /
• 2000

Using neural network approach, the diagnosis of faults in industrial process that requires observing multiple data simultaneously are studied. Two-stage diagnosis is proposed to analyze system faults. By using neural network, the first stage detects the dynamic trend of each normalized date patterns by comparing a proposed pattern. Instead of using neural network, the difference between stored fault pattern and real time data is used for fault diagnosis in the second stage. This method reduces the amount of calculation and saves storing space. Also, we dealt with unknown faults by normalizing the data and calculating the difference between the value of steady state and the data in case of fault. A model of tank reactor is given to verify that the proposed method is useful and effective to noise.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.519-521
• /
• 2000

Network reconfiguration is an operation task, and consists in the determination of the switching operations such to reach the minimum loss conditions of the distribution network. In this paper, an effective heuristic based switch scheme for loss minimization is given for the optimization of distribution loss reduction and a solution approach is presented. The solution algorithm for loss minimization has been developed based on the two stage solution methodology. The first stage of this solution algorithm sets up a decision tree which represent the various switching operations available, the second stage applies a proposed technique called cyclic best first search. Therefore, the solution algorithm of proposed method can determine on-off switch statuses for loss reduction, with a minimum computational effort.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.163-168
• /
• 2003

Analytical approach is applied to predict temperature of satellite box under worst hot condition from fairing jettison to separation. The box is tried to solve analytically which is exposed to known environmental heating condition and has internal heating and irradiation to space. For a single thermal mass, governing equation for temperature is simplified to 1st order ordinary differential equation(ODE) by several assumptions. Two cases are considered. The one is for constant mass box and the other is for mass-varying box. Each case has three different analytical solution by sign of constant term in ODE. One analytical solution for constant mass is applied to physical launch stage condition. It is concluded that the present analytical method can be used to quick predict the temperature of a satellite box and check whether a satellite is safe against space environment during launch stage.

• Journal of the Korean Society of Costume
• /
• v.55 no.7 s.98
• /
• pp.62-75
• /
• 2005

This study is focused on main performers' stage costumes in the 'Swan Lake', a masterpiece of classical ballet, which Is newly represented by Matthew Bourne, a choreographer. The objectives of the study is to help understand a trend of costume in modern public performance and art. First, this paper is attempted to describe the concept and the elements of ballet costume, secondly, to consider the performance generally, and finally to analyze main performers stage costumes. This study was performed by two processes; The first was to visit theaters to view the performances in person: the classical ballet by the Bolshoi Theater Ballet, the performance by Korea national ballet academy and the Matthew Bonne's modernly redefined ballet. The second was to review the regarding literatures and DVD. There are two apparent characteristics of main performers' stage costumes in modern-style ballet compared with classic-style ballet. First, there is an approach to gender identity; the character of swan with the classic tutu that has been the culmination of femininity in the classic-style ballet, used to be represented in an established idea on ballet costume, is now substituted by a creative idea, male ballerina and trouser-style ballet costume. Second, there is an approach to breaking the convention on the purpose of emphasizing popularity arousing real sympathy and art value. Also, modern-style ballet introduces bare body and ffot rather than tutu and toe-shoes, and adapts items from casual outfit fitted in earh performer's character with a present-day life.

• Journal of Power Electronics
• /
• v.18 no.4
• /
• pp.1027-1036
• /
• 2018

In this paper a new generalized space vector pulse width modulation scheme is proposed based on the principle of reverse mapping to drive the switches of multilevel inverters. This projected scheme is developed based on the middle vector of the subhexagon which holds the tip of the reference vector, which plays a major role in mapping the reference vector. A new approach is offered to produce middle vector of the subhexagon which holds tip of the reference vector in the multilevel space vector plane. By using middle vector of the subhexagon, reference vector is linked towards the inner two level sub-hexagon. Then switching vectors, switching sequence and dwell times corresponding to a particular sector of a two-level inverter are determined. After that, by using the two level stage findings, the switching vectors related to exact position of the reference vector are directly generated based on principle of the reverse mapping approach and do not need to be found at n level stage. In the reverse mapping principle, the middle vector of subhexagon is added to the formerly found two level switching vectors. The proposed generalized algorithm is efficient and it can be applied to an inverter of any level. In this paper, the proposed scheme is explained for a five-level inverter and the performance is analyzed for five level and three level inverters through MATLAB. The simulation results are validated by implementing the propose scheme on a V/f controlled three-level inverter fed induction motor using dSPACE control desk.

• Environmental and Resource Economics Review
• /
• v.23 no.3
• /
• pp.365-408
• /
• 2014

The purpose of this paper is to compare efficiencies, two stage efficiencies, and the reduction of economic growth due to the restraint of $CO_2$ and fossil fuel in two efficiency approach by pointing out the limit of traditional efficiency approach and introducing material balance approach. The efficiencies under the traditional approach and the material balance approach report significant gaps when they are analyzed in detail. Especially, in case not including fossil fuels, the low income countries show the bad performance of production efficiencies, but OECD and high-middle income countries reveal the better performance than that of the low countries. It fails to reflect the reality justly. Based on the material balance approach, the low income countries report the higher performance and the alleviated effect of environmental components for economic growth than OECD's.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11a
• /
• pp.46-51
• /
• 2001

To reach high areal density, less track pitch is expected and more servo bandwidth is required. One approach to overcoming the problem is by using dual stage servo system. In this system, a voice coil motor (VCM) is used as the primary stage while a milliactuator is used as the secondary stage. We have suggested new milliactuator based on the shear mode of piezoelectric elements to drive the head suspension assembly. In this paper, we introduce controller design method, PQ method. PQ method reduces the controller design problem for DISO(dual-input/single-output) systems to two standard controller design problems for SISO(single-input/single-output) problems. The first part of PQ method directly address the issue of actuator output contribution, and the second part allows the use of traditional loop shaping to achieve the overall system performance. This paper shows how to employ the PQ method to meet aggressive close-loop performance specifications for a disk drive system with a VCM and piezoelectric milliactuator.