• 대한기계학회논문집B
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• 제22권12호
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• pp.1702-1714
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• 1998

Removal of spilled oil over the sea and the river has become one of the urgent problems in these days. Removing oil using mechanical devices was recommended because chemical dispersion could cause the secondary contamination in the environment. In the present study a series of experiments were carried out to study the effect of operating conditions, especially, the angle between the belt and the fluid surface on the rate of recovery for the spilled oil using a belt skimmer. Three different types of operation, namely, upward pickup, downward pickup and up-and-downward pickup situations have been investigated for various contact angles, belt speeds and oil thicknesses to find the effects on the recovery rate. The highest rate of oil recovery was found in the case of a contact angle of $45^{\circ}$ and downward pickup. Furthermore, an optimal belt speed was found to reach the saturated recovery rate for a given oil thickness.

• 제어로봇시스템학회논문지
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• 제14권3호
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• pp.307-317
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• 2008

Relaxed static stability(RSS) concept has been applied to improve aerodynamic performance of modem version supersonic jet fighter aircraft. Therefore, flight control system are necessary to stabilize an unstable aircraft and provides adequate handling qualities. Also, flight control systems of modem version aircraft employ a safety system to support emergency situations such as a pilot unknown attitude flight conditions of an aircraft in night flight-testing. This situation is dangerous because the aircraft can lose if the pilot not take recognizance of situation. Therefore, automatic recovery system is necessary. The system called the "Pilot Activated Recovery System" or PARS, provided a pilot initiated automatic maneuver capable of an aircraft recoveries in situations of unusual attitudes. This paper addresses the concept of PARS and designed using nonlinear control law design process based on model of supersonic jet trainer. And, this control law is verified by nonlinear analysis and real-time pilot evaluation using in-house software. The result of evaluation reveals that the PARS support recovery of an aircraft unusual attitude and improve a safety of an aircraft.

• Membrane and Water Treatment
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• 제12권1호
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• pp.1-9
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• 2021

This study optimized the chemical cleaning process of discarded RO membranes for reuse in less demanding separation processes. The effect of physicochemical parameters, including the temperature, cleaning time, pH of the cleaning solution, and addition of additives, on the cleaning process was investigated. The membrane performance was evaluated by testing the flux recovery rate and salt rejection before and after the cleaning process. High temperatures (45-50 ℃) resulted in a better flux recovery rate of 71% with more than 80% salt rejection. Equal time for acid and base cleaning 3-3 h presented a 72.43% flux recovery rate with salt rejection above 85%. During acid and base cleaning, the best results were achieved at pH values of 3.0 and 12.0, respectively. Moreover, 0.05% concentration of ethylenediaminetetraacetic acid presented 72.3% flux recovery, while 69.2% flux was achieved using sodium dodecyl sulfate with a concentration of 0.5%; both showed >80% salt rejection, indicating no damage to the active layer of the membrane. Conversely, 0.5% concentration of sodium percarbonate showed 83.1% flux recovery and 0.005% concentration of sodium hypochlorite presented 85.2% flux recovery, while a high concentration of these chemicals resulted in oxidation of the membrane that caused a reduction in salt rejection.

• 대한전자공학회논문지TC
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• 제37권10호
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• pp.18-25
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• 2000

본 논문에서는 ATM망에서의 UBR 서비스를 이용한 네트워크 구성에서의 TCP 혼잡 제어 알고리즘에 따른 성능 분석을 하였다. TCP 혼잡 제어 알고리즘에는 Slow Start, Congestion Avoidance, Fast Recovery, Fast Retransmit등으로 이루어져 있다. TCP Reno, TCP Vanilla을 사용하여 ATM-UBR 서비스 망을 구축하여 성능을 비교 분석하였다. 그러나 Fast Retransmit, Recovery 알고리즘의 특성에 의하여 다중 패킷 손실이 발생할 때의 ATM-UBR 네트워크에서도 성능 저하 현상이 현저하게 발생하였다. 이러한 현상에 대한 해결책으로 본 논문은 새로운 Fast Retransmit, Recovery 알고리즘을 제시하여 성능을 개선하였다.

• 한국통신학회논문지
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• 제30권9C호
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• pp.877-886
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• 2005

Various frame recovery algorithms have been suggested to overcome the communication quality degradation problem due to Internet-typical impairments on Voice over IP(VoIP) communications. In this paper, we propose a new receiver-based recovery method which is able to enhance recovered speech quality with almost free computational cost and without an additional increment of delay and bandwidth consumption. Most conventional recovery algorithms try to recover the lost or erroneous speech frames by reconstructing missing coefficients or speech signal during speech decoding process. Thus they eventually need to modify the decoder software. The proposed frame recovery algorithm tries to reconstruct the missing frame itself, and does not require the computational burden of modifying the decoder. In the proposed scheme, the Vector Quantization(VQ) codebook indices of the erased frame are directly estimated by referring the pre-computed VQ Codebook Index Interpolation Tables(VCIIT) using the VQ indices from the adjacent(previous and next) frames. We applied the proposed scheme to the ITU-T G.723.1 speech coder and found that it improved reconstructed speech quality and outperforms conventional G.723.1 loss recovery algorithm. Moreover, the suggested simple scheme can be easily applicable to practical VoIP systems because it requires a very small amount of additional computational cost and memory space.

• 상하수도학회지
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• 제32권2호
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• pp.131-143
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• 2018

Phosphorus (P) is a limited, essential, and irreplaceable nutrient for the biological activity of all the living organisms. Sewage sludge ash (SSA) is one of the most important secondary P resources due to its high P content. The SSA has been intensively investigated to recover P by wet chemicals (acid or alkali). Even though $H_2SO_4$ was mainly used to extract P because of its low cost and accessibility, the formation of $CaSO_4$ (gypsum) hinders its use. Heavy metals in the SSA also cause a significant problem in P recovery since fertilizer needs to meet government standards for human health. Therefore, P recovery process with selective heavy metal removal needs to be developed. In this paper some of the most advanced P recovery processes have been introduced and discussed their technical characteristics. The results showed that further research is needed to identify the chemical mechanisms of P transformation in the recovery process and to increase P recovery efficiency and the yields.

• ETRI Journal
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• 제43권1호
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• pp.109-119
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• 2021

Self-recovery is a tamper-detection and image recovery methods based on data hiding. It generates two types of data and embeds them into the original image: authentication data for tamper detection and reference data for image recovery. In this paper, a region-based scalable self-recovery (RSS) method is proposed for salient-object images. As the images consist of two main regions, the region of interest (ROI) and the region of non-interest (RONI), the proposed method is aimed at achieving higher reconstruction quality for the ROI. Moreover, tamper tolerability is improved by using scalable recovery. In the RSS method, separate reference data are generated for the ROI and RONI. Initially, two compressed bitstreams at different rates are generated using the embedded zero-block coding source encoder. Subsequently, each bitstream is divided into several parts, which are protected through various redundancy rates, using the Reed-Solomon channel encoder. The proposed method is tested on 10 000 salient-object images from the MSRA database. The results show that the RSS method, compared to related methods, improves reconstruction quality and tamper tolerability by approximately 30% and 15%, respectively.

• 식품보건융합연구
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• 제7권3호
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• pp.25-32
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• 2021

This study examined the effects of kinesio taping on recovery from fatigue induced by an exercise of concentric contraction using an isokinetic machine. The fatigue was introduced by a mode of exercise at 60°/sec, 50 repetitions for three sessions. The changes of blood ammonia, lactate, LDH, and CK as a marker of fatigue were monitored. Eight healthy collegiate students participated in two experiments; 1) kinesio taping application condition and 2) no kinesio taping application condition. Before experiments, their physical characteristics were measured. For the experiment, blood samples were taken before and immediately after exercise, and 24hr as well as 72hr of recovery period. Window SPSS package 12.0 version was used and one-way ANOVA with repeated measures were employed. The results were as follows. 1) Blood ammonia tended to reduce along the recovery, but no differences between conditions were noticed. 2) Blood lactate tended to reduce during the recovery period, but differences between conditions were not noticed. 3) The LDH was not different between conditions and CK tended to reduce during the recovery period, but differences between conditions were not noticed. Based on the results, kinesio taping did not influence on recovery phase of blood ammonia, lactate concentration, LDH, and CK.

• 한국응급구조학회지
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• 제28권2호
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• pp.47-62
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• 2024

Purpose: This retrospective study analyzed the effects of advanced life support on the recovery of spontaneous circulation (SC) in patients with out-of-hospital cardiac arrest. Methods: The subjects of this study were out-of-hospital cardiac arrest patients transferred to the hospital by 119 paramedics in Gyeongsangbuk-do from January 1, 2021, to December 31, 2022, amounting to a total of 2,524 patients. Results: The younger the age, the higher the probability of recovery of spontaneous circulation, and it was higher when cardiac arrest occurred in a public place or was witnessed. If the patient's initial electrocardiogram rhythm is defibrillable, the probability of recovery from spontaneous circulation is high. The recovery of the spontaneous circulation rate decreased with time between the time of report and the time of contact with the patient. Recovery of the spontaneous circulation rate was high when mechanical chest compression devices and advanced airways were not used. Additionally, this study had positive effects on defibrillation, peripheral intravenous catheter insertion, and epinephrine infusion. Conclusion: Paramedics should actively perform peripheral intravenous catheter insertion and epinephrine infusion, and it should be possible to clearly determine whether defibrillation should be applied through electrocardiographic education.

• 전자공학회논문지C
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• 제36C권3호
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• pp.47-56
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• 1999

한국어를 연속적으로 발음할 때 여러 가지 음은변동이 일어난다. 이러한 음운변동은 한국어 연속 음성 인식을 어렵게 하는 주요 요인 중의 한가지이다. 본 논문에서는 음운변동이 반영된 음성 인식 문자열을 규칙에 의하여 text 기반 문자열로 다시 복원시키는 rule-based 시스템을 제안한다. 그리고 복원 결과들은 형태소 분석되어 올바른 문자열만 생성된다. 복원은 4가지 rule 즉, 음절 경계 종성 초성 복원 rule, 모음처리 복원 rule,끝음절 종성 복원 rule, 한 음절 처리 rule에 의거하여 이루어진다. 규칙 적용 과정 중에 효과적인 복원을 위해 x-clustering정보를 정의하여 사용하고, 형태소 분석기에 입력될 복원 후보수를 제안하기 위해 postfix음절 빈도정보를 구하여 사용한다. 본 시스템은 규칙기반 시스템이므로 대용량의 발음열 사전이나 음소열 사전을 필요로 하지 않고 문서 기반 형태소 분석기를 그대로 이용할 수 있다는 이점이 있다.