• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2389-2413
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• 2015

High data rates in long-term evolution (LTE) networks can affect the mobility of networks and their performance. The speed and motion of user equipment (UE) can compromise seamless connectivity. However, a proper handover (HO) decision can maintain quality of service (QoS) and increase system throughput. While this may lead to an increase in complexity and operational costs, self-optimization can enhance network performance by improving resource utilization and user experience and by reducing operational and capital expenditure. In this study, we propose the self-optimization of HO parameters based on fuzzy logic control (FLC) and multiple preparation (MP), which we name FuzAMP. Fuzzy logic control can be used to control self-optimized HO parameters, such as the HO margin and time-to-trigger (TTT) based on multiple criteria, viz HO ping pong (HOPP), HO failure (HOF) and UE speeds. A MP approach is adopted to overcome the hard HO (HHO) drawbacks, such as the large delay and unreliable procedures caused by the break-before-make process. The results of this study show that the proposed method significantly reduces HOF, HOPP, and packet loss ratio (PLR) at various UE speeds compared to the HHO and the enhanced weighted performance HO parameter optimization (EWPHPO) algorithms.

• 융합정보논문지
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• 제8권5호
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• pp.229-236
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• 2018

과거 기술사업화는 학계 및 연구계 중심으로 기술이전 또는 창업지원 등 좁은 의미로 해석되어 시행되었으며, 기술 사업화 단계에서 사업의 경험부족, 기술개발 실패, 판로 미확보 등이 실패원인으로 지적되어 왔다. 본 논문에서는 학계 연구소 보유기술의 직접사업화 지원 사업이 공공 자금 및 대기업 영업력을 기반으로, 사업화 기술과 자본, 판로, 정부정책 및 지원 등이 결합한 신개념의 기술사업화 모델을 제시하고, 보유기술을 직접사업화하기 위한 애로요인을 도출하였으며, 조사 및 분석을 통해 기술사업화 수행 주체의 요구요인과 보유역량과의 사이에 차이가 있고, 요구요인과 애로요인간에 상관관계가 있다는 유의미한 결론에 도달하였다. 이 결론을 기반으로, 대학 및 연구기관 보유기술에 대한 사업화의 효율성을 높이기 위한 일환으로 지원정책 개선 방안을 도출하였다.

• 한국지반환경공학회 논문집
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• 제16권4호
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• pp.23-32
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• 2015

This paper addresses the effects of extreme rainfall on the stability of cut slopes in Yen Bai city, Northern Viet Nam. In this area, natural slopes are excavated to create places for infrastructures and buildings. Cut slopes are usually made without proper site investigations; the design is mostly based on experience. In recent years, many slope failures have occurred along these cuts especially in rainy seasons, resulting in properties damaged and loss of lives. To explain the reason that slope failure often happens during rainy seasons, this research analyzed the influence of extreme rainfalls, initial ground conditions, and soil permeability on the changes of pore water pressure within the typical slope, thereafter determining the impact of these changes on the slope stability factor of safety. The extreme rainfalls were selected based on all of the rainfalls triggering landslide events that have occurred over the period from 1960 to 2009. The factor of safety (FS) was calculated using Bishop's simplified method. The results show that when the maximum infiltration capacity of the slope top soil is less than the rainfall intensity, slope failures may occur 14 hours after the rain starts. And when this happens, the rainfall duration is the deciding factor that affects the slope FS values. In short, cut slopes in Yen Bai may be stable in normal conditions after the excavation, but under the influence of tropical rain storms, their stability is always questionable.

• Advances in pediatric surgery
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• 제4권1호
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• pp.1-15
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• 1998

To evaluate the effectiveness of central venous catheters(CVCs) in children, 320 CVCs placed in 255 neonate and children over a 10-year period were analyzed retrospectively. CVC was placed by one pediatric surgeon for a total of 6, 116 patients days. Catheters were placed preoperatively for TPN or chemo in 223 cases. CVC was solely for TPN in 57 cases and for chemotherapy in 40. Local anesthesia was utilized in 71 cases, and the general anesthesia was administered in the remainder of the patients. The subclavian vein was catheterized(SCV) in 202 cases(82 infants and neonates), tunneled external jugular venotomy(EJV) was utilized in 38, tunneled internal jugular venotomy(UV) in 2, the facial venotomy(FV) was used in 3, and the umbilical vein was catheterized UVC) with vein transposition in 74 infants. In neonates, 72 UVCs were placed during laparotomy. SCV was increased with ages, from 3 kg of minimal body weight. The average catheter-periods over-all were 19.1 days, SCV 17 days, EJV 40, IJV 60 and UVC 14. Technical complications were; arterial puncture(6), puncture failure(5) and abnormal location(12) in SCV; insertion failure(3) in EJV; abnormal location in the portal vein(4) and the liver parenchyma(2) cystic fluid accumulations in UVC. Twelve migrations(3.8 %) out of position occurred; SCV(2), EJV(1) and UVC(9). There were 4 cases(1.2 %) of catheter obstruction and 11(3.4 %) of catheter infection(3 SCV, 2 EJV and 6 UVC). Rescue procedures were utilized with some success. There was one mortality(0.3 %) due to deep sedation in a 1.06 kg baby during placement of an EJV. The surgeon's experience, proper catheter selection and following safety rules are the most important factors for successful CVCs.

• Clinical and Experimental Pediatrics
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• 제52권1호
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• pp.129-132
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• 2009

저자들은 청색증과 끙끙거림, 심비대로 전원되어 심장 초음파 검사에서 좌심실에 발생한 단독 심실 비치밀화증을 가진 신생아 1예를 경험하였다. 환자에서 측정한 NT pro-BNP는 높았고, 수유 곤란과 빈호흡을 동반한 심부전 증상이 있었다. 심부전증에 대한 치료에도 불구하고 주기적으로 시행한 NT pro-BNP가 더 높아지면서 환자에게서 급성 심정지가 발생하였고, 심폐소생술 이후 NT pro-BNP가 다시 낮아지면서 심부전 등의 증상은 호전을 보였다. 심초음파 검사와 함께 NT pro-BNP를 주기적으로 검사해 보는 것이 병의 경과를 예측하는데 도움이 될 수 있을 것이다.

• 한국도로학회논문집
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• 제14권5호
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• pp.31-45
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• 2012

PURPOSES: In Korea, rapid maintenance of distressed concrete pavement is required to prevent traffic jam of the highway. Asphalt concrete overlay has been used as a general maintenance method of construction for aged concrete pavement. AC overlay on existing concrete pavements experience various early distresses such as reflection crack, pothole and rutting, due to different physical characteristics between asphalt overlay and existing concrete pavement. Bonded concrete overlay(BCO) is a good alternative since it has advantages that can reduce various distresses during the service life since overlay material has similar properties with existing concrete pavements. Recently, BCO which uses the ultra rapid harding cement has been applied for maintenance of highway. BCO has advantage of structural performance since it does monolithic behave with existing pavement. Therefore, it is important to have a suitable bond strength criteria for securing performance of BCO. Bond strength criteria should be larger than normal tensile stress and horizontal shear stress occurred by traffic and environmental loading at bond interface. Normal tensile stress and horizontal shear stress need to estimated for the establishment of practical bond strength criteria. METHODS: This study aimed to estimate the bond stresses at the interface of BCO using the three dimensional finite element analysis. RESULTS: As a result of this study, major failure mode and maximum bond stress are evaluated through the analysis of normal tensile stress and horizontal shear stress for various traffic and environmental load conditions. CONCLUSIONS: It was known that normal tensile stresses are dominated by environmental loading, and, horizontal shear stresses are dominated by traffic loading. In addition, bond failure occurred by both of normal tensile stresses and horizontal shear stresses; however, normal tensile stresses are predominated over horizontal shear stresses.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.3-10
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• 2003

Soil and groundwater contamination by petroleum hydrocarbon products is only one of many environmental problems in Korea. However, many environmental consulting companies have been targeted their business on this subject because the petroleum-oil-lubricant (POL) products have been widely used product and accidental releases of the products from storages resulted numerous small and large contaminated sites throughout Korea. Therefore, many small and large companies are actively participating in environmental assessment and remediation projects for the POL contaminated sites. Remedial technologies for the POL contaminated sites have been developed for many years by government and private institutions throughout the world. Development of a new decontamination technology for the POL contaminated sites is no longer attractive issue in research community because scientific bases of most cost-effective remedial technologies are well understood and have been used in the field by commercial sector. Numerous sites contaminated by underground tanks at gas stations have been remediated by relatively small companies in this country. We should appreciate their noticeable contributions as a frontier under very difficult market environment in Korea. We heard many successful stories as well as a few failure stories. Soil-groundwater remediation of POL contaminated site is not a simple task as shown in the text books or protocols. Therefore, failure risk is always with us, which requires continuous efforts for improvement of the technologies by the users and developers. In this presentation, author will discuss technical problems encountered and improvement made during implementation of several remedial technologies applied by Samsung Environmental Team. This is not a presentation about research or case study. We want to share our thought and experience with environmental engineers actively engaged in soil and groundwater remediation projects in Korea.

• Asian Pacific Journal of Cancer Prevention
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• 제15권5호
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• pp.2279-2285
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• 2014

Background: To evaluate treatment outcomes of patients with stage I-III endometrial cancer treated with postoperative radiation. Materials and Methods: A retrospective review of 166 endometrial cancer patients, undergoing surgery and postoperative radiotherapy at Siriraj Hospital from 2005-2008 was performed. Pathology was reviewed. Results of treatment were reported with 5-year loco-regional recurrence free survival (LRRFS), 5-year overall survival (OS), patterns of failure and toxicity, and according to stage and risk groups. Results: Median follow up time was 62.8 months. Pathological changes were found in 36.3% of the patients after central reviews, leading to 19% changes in risk groups. Most of the patients (83.7%) received pelvic radiation (PRT) and vaginal brachytherapy (VBT). Five-year LRRFS and OS of all patients were 94.9% and 85.5%, respectively. There was no recurrence or death in low and low-intermediate risk groups. For the high-intermediate risk group, 5-year LRRFS and OS were 96.2% and 90.8%, respectively, and for the high risk group 90.5% and 71%. Late grade 3 and 5 gastrointestinal toxicity was found in 3% and 1.2% of patients, respectively. All of them received PRT 5,000 cGy in 25 fractions. Conclusions: Low and intermediate risk patients had good results with surgery and adjuvant radiation therapy. For high risk patients, postoperative radiation therapy alone appeared to be inadequate as the most common pattern of failure was distant metastasis.

• 한국산림과학회지
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• 제84권3호
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• pp.394-405
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• 1995

온대 삼림지대에서 산화 적지나 개벌 적지에 왕성하게 번성하는 것이 ericaceous속이다. ericaceous속의 식물들은 성장이 빨라서 다른 종과의 경쟁에서 유리하고 또한 allelopathy 효과 때문에 침엽수 갱신에 영향을 미친다. Kalmia가 번성하는 지역에서는 삼림 갱신이 잘 되지 않거나 조림한 침엽수의 생장이 저조하였다. 이러한 생상 저해 현상은 서유럽의 Calluna - Sitca spruce - Scots pine 생태계와 미국의 북서 태평양 지역의 Gaultheria - cedar/hemlock 생태계에서도 나타나고 있다. 삼림이 파괴된 다음에 Kalmia - black spruce 생태계의 다양한 변화는 침엽수 생장을 저해하거나 갱신을 방해하는 원인으로 생각되어지고 있다. 양분경쟁에 대한 논쟁의 여지는 있으나 Kalmia는 black spruce 생장을 억제하는 주원인으로 작용한다. 여러 곳의 야외, 실내 및 온실에서 한 실험 결과는 이러한 결론을 뒷받침해 주고 있다. 본 논문에서는 Kalmia 잎으로부터 8가지의 폐놀물질을 분리동정해 냈으며 이들 중 4가지는 black spruce에 고도의 독성을 나타냈다. Kalmia 우점지역에서 allelopathic 영향을 적게 하므로써 black spruce의 갱신을 증진시키기 위한 여러 가지 방법에 대한 고찰을 하였다.

• Journal of Chest Surgery
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• 제25권1호
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• pp.32-41
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• 1992

From August 1982 to December 1991, 58 consecutive infants with tetralogy of Fallot underwent primary repair. Age ranged from 22 days to twelve months [n=58, 8.7$\pm$2.7 months] and body weight from 3.1 to 13 kilograms [n=58, 7.8$\pm$1.7 kilograms]. Qne infant had absence of the pulmonary valve; one had Ebstein`s anomaly and one had supramitral ring. Thirty-two patients [56%] experienced anoxic spell. Preoperative pulmonary artery indices were measured in 38 cases, ranging 126-552mm2/M2BSA[n=38, 251$\pm$79mm2/M2BSA]. All infants required a right ventricular outflow tract patch; in 41, the patch extended across the pulmonary valve annulus, in 13 of them, monocusps were constructed. All had patch closure of ventricular septal defect. Two infants had REV operation for avoiding injury to the canal branch of the right coronary artery which cross the right ventricular out flow tract. Post repair PRV/LV were measured at operating room in 40 cases, which revealed mean value of 0.49$\pm$0.12 [range: 0.25-0.74]. The hospital mortality was 10.3% [6 patients], and causes of deaths were right heart failure due to sustained right ventricular hypertension[4] and right ventricular outflow tract obstruction, intractablesuraventricular tachyarrhythmia[1], hypoxia[1] due to residual right to left shunt across the atrial septal defect in patient associated with Ebstein`s anomaly. All infants were doing well at follow-up from 1 to 101 months[20.6 months /patient, 1, 072 patient-month] Serial postoperative echocardiograms revealed no residual ventricular septal defects and estimated RVOT gradients between 0 and 40 mmHg except 3 cases [50, 50, 60 mmHg]. There were no late deaths and late ventricular arrhythmias or congestive heart failure. Redo operations were done in 2 cases because of residual right ventricular outflow tract obstruction. This experience with infants with tetralogy of Fallot suggests that, if mortality is tolerable, eletive repair of tetralogy of Fallot could be reasonably undertaken during the first year of life, and even better results could be anticipated along with improvement of methods of myocardial protection and postoperative care.