• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
• /
• pp.312-316
• /
• 2004

Single-well tracer tests, especially push pull tracer tests, are more effective to estimate hydraulic parameters and microbial metabolic activities in terms of duration and cost compared to multi-well tracer tests. However, there are some drawbacks in accuracy, complicated data analysis and uniqueness. These shortages are thought to be derived from the applied conditions which affect mass recovery curve and breakthrough curve. Factors such as extraction rate, resting period, hydraulic conductivity and hydraulic gradient are considered as the major factors determining the mass recovery rate and shape of the breakthrough curve. The results of the sensitivity analysis are summarized as follows: 1) the significant change in concentration of breakthrough curve is obtained when the extraction rate increases. This effect would also be much higher if the hydraulic conductivity is lower; 2) the mass recovery rate decreases with the increase of resting time, and the difference of mass recovery rates for different resting times is inversely proportional to the hydraulic conductivity; 3) the sensitivity values decrease with time. The hydraulic conductivity affects not only the early period, but the later period of the breakthrough curves; 4) The influence of the hydraulic gradient on the breakthrough curves is greater at earlier stage than at later stage. The mass recovery rate is inversely proportional to the hydraulic gradient.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
• /
• pp.711-712
• /
• 2006

For the application of superconducting fault current limiters(SFCLs) to the protection system, quench recovery characteristics of Au/YBCO thin film were investigated. The Au/YBCO thin film was designed as a SFCL element with a bi-spiral pattern. The SFCL element limited the fault current successfully. For the analysis of the recovery to superconducting state, we measured resistance variation of the SFCL element after the quench. In addition, in order to investigate the dependence of quench characteristics of SFCL on the $LN_2$ cooling condition, we measured the recovery time under a pressure of 1, 2 and 3 atm. As the results, the recovery time increased in proportion to the duration of the fault currents. In the sub-cooled condition, while the quench development was exactly the same, the recovery time was shortened as the pressure increased.

• 한국전문물리치료학회지
• /
• 제1권1호
• /
• pp.67-74
• /
• 1994

Our purpose of this study was to determine the most effective cool-down exercise. The recovery times of dynamic strength after isometric and isotonic cool-down exercise were measured immediately post cool-down exercise, 30 seconds later and 60 seconds later in 30 normal, healthy men from 19 to 29 years, using dumbells(Model, Iron). The recovery time of dynamic strength had a significant positive correlation with isotonic and isometric cool-down exercise using the Chi-square method (p<0.01). Sources of significant differences were determined by the Wilcoxon signed-ranks test (p<0.01). The isometric cool-down exercise significantly shortened the recovery time of dynamic strength. We suggest that the isometric cool-down exercise may be more effective than isotonic cool-down exercise in shortening the recovery time of dynamic strength.

• 전기학회논문지P
• /
• 제59권4호
• /
• pp.477-480
• /
• 2010

Fault current in power system is expected to increase by demand of power capacity. Therefore, when the fault occurred, fault current was increased in the power system. Many studies have been progressed to limit the fault current. Superconducting fault current limiter (SFCL) is one of them which has been studied in worldwide. In this paper, we will analyze characteristics of a transformer-type SFCL by reclosing operation when the voltage increases. Twice opening times in the reclosing of circuit breaker were set as the 0.5 and 15 seconds, respectively. Turn's number of primary and secondary coils set 4:2 and we increased voltages from 120V to 280V for each experiment. By the current waveform, maximum fault current in second and third cycles was lowered when the voltage was increased. In the recovery waveform, recovery time was increased as the voltage was increased. The reason was that power burden of the SFCL increased when consumption power was increased, so the time to get back to SFCL took longer. We compared the characteristics of a resistive-type and transformer-type SFCL. As a result, we found that the fault current of a transformer-type was lower than resistive-type and recovery time of the SFCL was shorter. Consequently, transformer-type SFCL was more profitable for limitation of fault current and recovery time under the same condition for reclosing operation.

• Archives of Plastic Surgery
• /
• 제41권5호
• /
• pp.486-492
• /
• 2014

Background We conducted this study to identify the correlation between the time to surgery and that to recovery from postoperative diplopia. Methods In the current single-center, retrospective study, we enrolled a total of 11 patients (n=11) who were diagnosed with white-eyed blowout fracture and underwent surgical operation at our institution between January 2009 and January 2013. To identify the correlation between the time to surgery and that to recovery from postoperative diplopia, we divided our patients into the three groups: the group A (time to surgery, <2 days) (n=4), the group B (time to surgery, 3-7 days) (n=4) and the group C (n=3) (time to surgery, 8-60 days). Then, we compared such variables as sex, age, signs of soft tissue injury, preoperative nausea/vomiting, the degree of preoperative diplopia and the side of the fracture on computed tomography scans between the three groups. Results In our series, mean age at the onset of trauma was nine years (range, 5-16 years); the mean time to surgery was 30 days (range, 2-60 days); and the mean follow-up period was one year (range, 6 months-2 years). Our results showed that the time to recovery was shorter in the patients with a shorter time to surgery. Conclusions We found that the degree of recovery from impaired ocular motility and diplopia was the highest in the patients undergoing surgical operations within 48 hours of the onset of trauma with the reconstruction of the fracture sites using implant materials.

• 한국통신학회논문지
• /
• 제29권7B호
• /
• pp.650-659
• /
• 2004

국내 무선 네트워크 환경은 사용자의 서비스 요구 수용과 시장 성장으로 인해 빠르게 변화하고 있다. 이에 따라 무선 구간에서 TCP(transmission control protocol)를 이용한 신뢰성 있는 데이터 전송도 늘어날 전망이다. TCP는 유선 네트워크에서 사용함을 가정으로 만들어졌기 때문에 무선에서 발생할 수 있는 비 혼잡 손실에 의해 많은 성능 저하를 겪을 수 있다. 특히 RTO(retransmission timeout)은 TCP의 성능에 많은 영향을 미친다. 본 논문에서는 송신단에서 fast recovery과정 중에 발생한 패킷 손실을 빠르게 감지하여 RTO없이 복구함으로써 성능저하를 줄일 수 있는 DAC$^{＋}$(Duplicate Acknowledgement Counting)와 EFR(Extended Fast Recovery)을 제안한다. 제안 알고리듬을 TCP NewReno와 비교했을 때 정상 상태에서 fast recovery 확률이 높고, 이에 따른 RTO 감소로 인해 response time이 줄어드는 것을 확인할 수 있다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권8호
• /
• pp.3825-3828
• /
• 2014

Surgical outcomes of colorectal cancer treatment depend not only on good surgery and tumor biology but also on an optimal perioperative care. The enhanced recovery program (ERP) - a multidisciplinary and multimodal approach, or so called 'fast-track surgery' - has been designed to minimize perioperative and intraoperative stress responses, and to support the recovery of organ function aiming to help patients getting better sooner after surgery. Compared with conventional postoperative care, the enhanced recovery program results in quicker patient recovery, shorter length of hospital stay, faster recovery of gastrointestinal function, and a lower incidence of postoperative complications. Although not firmly established as yet, the enhanced recovery program after surgery could be of oncological benefit in colorectal cancer patients because it can enhance recovery, maintain integrity of the postoperative immune system, increase feasibility of postoperative chemotherapy, and shorten the time interval from surgery to chemotherapy. This commentary summarizes short-term outcomes and potential long-term benefits of enhanced recovery programs in the treatment of colorectal cancer.

• Journal of Power Electronics
• /
• 제15권2호
• /
• pp.338-345
• /
• 2015

The time-optimal control for boost converters can achieve the minimum recovery time. However, their output voltage deviation is quite large. Since the minimum output voltage deviation and minimum recovery time cannot be obtained at the same time, a novel energy control is proposed to achieve a superior tradeoff between them in this paper. The peak value of the inductor current can be decreased as well. Its control parameter is easy to choose. When compared with the conventional control methods, the proposed control shows a better dynamic performance. Experimental results, which are in agreement with the theoretical analysis, are provided to verify the proposed control method.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제9권10호
• /
• pp.4160-4176
• /
• 2015

Data compression like image and video compression has come a long way since the introduction of Compressive Sensing (CS) which compresses sparse signals such as images, videos etc. to very few samples i.e. M < N measurements. At the receiver end, a robust and efficient recovery algorithm estimates the original image or video. Many prominent algorithms solve least squares problem (LSP) iteratively in order to reconstruct the signal hence consuming more processing time. In this paper non-iterative threshold based recovery algorithm (NITRA) is proposed for the recovery of images and videos without solving LSP, claiming reduced complexity and better reconstruction quality. The elapsed time for images and videos using NITRA is in ㎲ range which is 100 times less than other existing algorithms. The peak signal to noise ratio (PSNR) is above 30 dB, structural similarity (SSIM) and structural content (SC) are of 99%.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.1201-1204
• /
• 1996

The previous results on LTR methods for time delay systems need the solution of the operator-type Riccati equation. In addition, it can be difficult to make the target loop shape representing the design specification. This paper proposes a new LTR method for input-delayed systems using well-established LTR method for non-delay systems. For doing this, a time delay margin is derived and the time delay of the input-delayed systems is assumed less than equal to the time delay margin. A simple example is presented for illustrations.