• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.988-991
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• 1996

The purpose of this thesis is to develop methods of designing robust LQR/LQG controllers for time-varying systems with real parametric uncertainties. Controller design that meet desired performance and robust specifications is one of the most important unsolved problems in control engineering. We propose a new framework to solve these problems using Linear Matrix Inequalities (LMls) which have gained much attention in recent years, for their computational tractability and usefulness in control engineering. In Robust LQR case, the formulation of LMI based problem is straightforward and we can say that the obtained solution is the global optimum because the transformed problem is convex. In Robust LQG case, the formulation is difficult because the objective function and constraint are all nonlinear, therefore these are not treatable directly by LMI. We propose a sequential solving method which consist of a block-diagonal approach and a full-block approach. Block-diagonal approach gives a conservative solution and it is used as a initial guess for a full-block approach. In full-block approach two LMIs are solved sequentially in iterative manner. Because this algorithm must be solved iteratively, the obtained solution may not be globally optimal.

• The Korean Journal of Pain
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• 제9권2호
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• pp.336-339
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• 1996

Stellate ganglion block which usually practiced in pain clinics may combined with hemodynamic changes because it blocks sympathetic nerve chains. We measured the hemodynamic changes with NCCOM3-$R7^{(R)}$ (BOMED, U.S.A.) which applicated bioimpedance method in twenty-two patients. Mean arterial pressure, heart rate, cardiac output, ejection fraction and left ventricle end diastolic volume (LEDV) were measured before stellate ganglion block (control), 1, 3, 5, 10 and 20 minutes after stellate ganglion block with 8 ml of 0.25% bupivacaine. The results were as follows: Mean arterial pressure decreased significantly (p<0.05) in 10, 20 minutes after stellate ganglion block comparing to control, but not clinically significant. Heart rate, cardiac output, ejection fraction and LVEDV showed no significant change compared to control value. These results showed that stellate ganglion block is a safe technique without significant hemodynamic changes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.626-630
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• 2005

This paper presents a novel Intelligent-Welding-Carriage (IWC) for automation of curved block in shipbuilding. The curved block is usually used in both front and back side of the ship. In curved block root gap is big, $1{\sim}7$ [mm] and inclination, $0{\sim}30$ [deg]. Since available conventional carriage type is limited to use below root gap of 3 [mm], only manual welding is employed in curved block. To adopt an IWC in curved block, it requires control of the welding conditions, i.e., voltage, current and travel speed, with respect to root gap and inclination to achieve good welding quality. In this paper, an IWC is developed for automization of welding operation to accommodate gap and inclination. Kinematics model and dynamics using Lagrangian formulation of the manipulator is introduced. IWC utilizes a database to perform accurate welding. The database is programmed based on numerous experimental test results with respect to gap, inclination, material, travel speed, weaving condition, voltage, and current. Finally, experimental result using PID control is addressed for verify the trajectory tracking accuracy of end-effector.

• 한국통신학회논문지
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• 제27권12C호
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• pp.1282-1287
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• 2002

본 논문에서는 가정 내의 전화선을 이용한 홈 네트워크 기술인 10Mbps HomePNA(Home Phoneline Networking Alliance) 20 PHY 회로의 설계 및 그에 대한 검증방법을 보여 준다. HomePNA 2.0 PHY 회로는 MII(Media Independent Interface)와 AFE 인터페이스에 의해 외부와 연결된다. 설계된 10Mbps HomePNA 2.0 PHY의 회로의 전체 구조는 Management block IEEE 802.3 CSMA/CD MAC(Media Access Control) block, 변조 및 복조 block으로 크게 구성된다. 설계된 회로는 프로토타입 FPGA PCB 보드를 이용하여 검증하였다. 또한, Linux 기반의 드라이버 프로그램을 개발하여 HomePNA 프레임 데이터 전송의 기본적인 동작을 확인하였으며, HomePNA 2.0 링크 계층 프로토콜의 RNCF(Rate Negotiation Control Function)에 의하여 전송속도의 변화를 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권6호
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• pp.1600-1619
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• 2023

Organizations and other institutions have recently started using cloud service providers to store and share information in light of the Internet of Things (IoT). The major issues with this storage are preventing unauthorized access and data theft from outside parties. The Block chain based Security Sharing scheme with Data Access Control (BSSDAC) was implemented to improve access control and secure data transaction operations. The goal of this research is to strengthen Data Access Control (DAC) and security in IoT applications. To improve the security of personal data, cypher text-Policy Attribute-Based Encryption (CP-ABE) can be developed. The Aquila Optimization Algorithm (AOA) generates keys in the CP-ABE. DAC based on a block chain can be created to maintain the owner's security. The block chain based CP-ABE was developed to maintain secures data storage to sharing. With block chain technology, the data owner is enhancing data security and access management. Finally, a block chain-based solution can be used to secure data and restrict who has access to it. Performance of the suggested method is evaluated after it has been implemented in MATLAB. To compare the proposed method with current practices, Rivest-Shamir-Adleman (RSA) and Elliptic Curve Cryptography (ECC) are both used.

• 대한족부족관절학회지
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• 제20권3호
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• pp.135-139
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• 2016

Purpose: Modified Mau and Akin osteotomy for hallux valgus is followed by moderate to severe postoperative pain. Ultrasound-guided sciatic nerve block can be an effective option for pain control. We attempted to evaluate the efficacy of the ultrasound-guided sciatic nerve block in controlling postoperative pain. Materials and Methods: The charts of 59 consecutive patients were retrospectively reviewed between December 2014 and August 2015. Twenty-eight patients (the patient group) has received the ultrasound-guided sciatic nerve block after surgery, and 31 patients (the control group) has not received such procedure. The primary outcome was the satisfaction scale for postoperative pain control and postoperative visual analogue scale (VAS) score. Results: The VAS score at postoperative day one was significantly lower in the patient group than in the control group. The satisfaction scale for pain control for postoperative 1 day was significantly different between the two groups. In patient group, most patients have rated positively ('strongly agree' 42.9%, 'agree' 42.9%); however, in the control group, the rating scales were distributed relatively negatively ('strongly agree' 9.7%, 'agree' 22.6%, 'neutral' 29.0%, 'disagree' 25.8%, 'strongly disagree' 12.9%). The number of postoperative rescue analgesics injection was significantly lower in the patient group than in the control group. Conclusion: Postoperative ultrasound-guided sciatic nerve block was effective for pain relief after hallux valgus surgery.

• The Korean Journal of Pain
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• 제12권1호
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• pp.43-47
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• 1999

Backgroud: Systemic administration of opioid can prolong the duration of epidural anesthesia. The authors examined the effect of nitrous oxide ($N_2O$) on the level of sensory block induced by epidural lidocaine. Methods: Twenty minutes after epidural injection of 2% lidocaine (below 70 years : 20 ml, 70 years and above : 15 ml), the level of sensory block was assessed (2nd stage). Patients were randomly assigned to receive either medical air (control group, n=15) or 50% $N_2O$ in oxygen ($N_2O$ group, n=15) for 10 minutes, the level of block was reassessed (3rd stage). Pateints were given room air (control group) or 100% oxygen for 5 minutes and room air for 5 minutes ($N_2O$ group), and the level of block was reassessed (4th stage). Results: At the 3rd stage, $N_2O$ group showed 4.3 cm cephalad increase in the level of sensory block (p=0.005), but control group revealed 1.43 cm regression. After discontinuation of gas, the level of block regressed in both group (p=0.000). At the 4th stage, $N_2O$ group revealed 3.5 cm cephalad increase (p=0.048) and control group 1.97 cm regression (p=0.001) as compared with the 2nd stage. Conclusions: The level of sensory block induced by epidural lidocaine was significantly increased cephalad by concommitant use of 50% $N_2O$ for 10 minutes.

• The Korean Journal of Pain
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• 제34권4호
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• pp.487-500
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• 2021

Background: Although the erector spinae plane block has been used in various truncal surgical procedures, its clinical benefits in patients undergoing spinal surgery remain controversial. The aim of this meta-analysis was to evaluate the clinical benefits of erector spinae plane block in patients undergoing spinal surgery. Methods: We searched the Cochrane Library, PubMed, EMBASE, and China National Knowledge Infrastructure for randomized controlled trials comparing the erector spinae plane block with a nonblocked control for spinal surgery. Results: Twelve studies encompassing 696 subjects were included in our systematic review and meta-analysis. We found that the erector spinae plane block decreased postoperative pain scores and opioid consumption in the postoperative and intraoperative periods. Moreover, it prolonged the time to the first rescue analgesic, reduced the number of patients who required rescue analgesia, and lowered the incidence of postoperative nausea and vomiting. However, it did not exhibit efficacy in decreasing the incidence of urinary retention and itching or shortening the length of hospital stays, or the time to first ambulation. Conclusions: Erector spinae plane block improves analgesic efficacy among patients undergoing spinal surgery compared with nonblocked controls; however, there is insufficient evidence regarding the benefits of erector spinae plane block for rapid recovery.

• 제어로봇시스템학회논문지
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• 제9권11호
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• pp.899-905
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• 2003

An intermediate images generation method using multi-resolution based hierarchical block matching disparity map is proposed. This method is composed of a disparity estimation, an occlusion detection and intermediate image synthesis. For the disparity estimation, which is one of the important processes in intermediate image synthesis, we use the multi-resolution based hierarchical block matching algorithm to overcome the imperfect ness of block matching algorithm. The proposed method makes disparity maps more accurate and dense by multi-resolution based hierarchical block matching, and the estimated disparity maps are used to generate intermediate images of stereo images. Generated intermediate images show 0.1∼1.4 ㏈ higher PSNR than the images obtained by block matching algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1-4
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• 1996

It is difficult that a non-translational motion in a block is estimated by the block matching algorithm (BMA). In this paper, a nodal-displacement-based deformation model is used for this reason. This model assumes that a selected number of control nodes move freely in a block and that displacement of any interior point can be interpolated from nodal displacements. As a special case with a single node this model is equivalent to a translational model. And this model can represent more complex deformation using more nodes. We used an iterative gradient based search algorithm to estimate nodal displacement. Each iteration involves the solution of a simple linear equation. This method is called the deformable block matching algorithm (DBMA).