• Journal of information and communication convergence engineering
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• 제9권6호
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• pp.753-757
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• 2011

The possibility of implementing nonuniform residual dispersion per span (RDPS) in optical links with net residual dispersion (NRD) controlled by precompensation and postcompensation for 960 Gbps WDM transmissions is studied and discussed. The fiber optic communication links investigated in this paper consist of inline dispersion management (DM) for each fiber spans and optical phase conjugator (OPC) at mid-way of total transmission length in order to compensate for WDM signal distortions due to group velocity dispersion (GVD) and nonlinearities. It is confirmed that the effect of nonuniform RDPS distribution on system performance is not significant. It is also confirmed that the optimal NRD is obtained to be one of two values of +10 ps/nm or -10 ps/nm, which depend on the deciding of NRD controlled by precompensation or postcompensation, and the exact RDPS configurations. The effective NRD ranges resulting eye opening penalty (EOP) below 1 dB are independent on the exact RDPS distribution for relative low launch power. Therefore, results show the possibility of implementing the flexible optical links to expand network construction for WDM transmission of high bit-rate capability.

• International Journal of Internet, Broadcasting and Communication
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• 제12권4호
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• pp.83-92
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• 2020

A recent study to determine the fall is focused on analyzing fall motions using a recurrent neural network (RNN), and uses a deep learning approach to get good results for detecting human poses in 2D from a mono color image. In this paper, we investigated the improved detection method to estimate the position of the head and shoulder key points and the acceleration of position change using the skeletal key points information extracted using PoseNet from the image obtained from the 2D RGB low-cost camera, and to increase the accuracy of the fall judgment. In particular, we propose a fall detection method based on the characteristics of post-fall posture in the fall motion analysis method and on the velocity of human body skeleton key points change as well as the ratio change of body bounding box's width and height. The public data set was used to extract human skeletal features and to train deep learning, GRU, and as a result of an experiment to find a feature extraction method that can achieve high classification accuracy, the proposed method showed a 99.8% success rate in detecting falls more effectively than the conventional primitive skeletal data use method.

• The Korean Journal of Ecology
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• 제24권4호
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• pp.227-232
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• 2001

The biomass structure for three major components viz., the dominant grass, Chrysopogon zeylanicus Thw., the 'other grasses' and the'remaining species'and dry matter dynamics for total community were studied over a period of one year in an annual fire influenced subtropical humid grassland community in Western Ghats, India. The biomass of aboveground, belowground and litter compartments were high as in other humid grasslands and generally have positive correlation with rainfall, rainy days and relative humidity with the exception of litter parts. The above and belowground net primary productions (4,561 and 722 g/㎡, respectively) were also higher and were comparable with other humid tropical grasslands. The turnover of organic matter was rapid, Of the total input of 14.47 g/㎡ into the system, about 86.3% was allocated to above ground parts and 13.7% to below ground parts. The total disappearance was 2.56 g/㎡ and it was accounted to be 17.68% of the total output. The net surplus of dry matter (82.32%) in the post fire community indicates that the grassland was maintained in a seral stage. Hence it is suggested that prescribed burning may keep this ecosystem in a highly productive and seral stage.

• 한국정보통신학회논문지
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• 제18권2호
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• pp.415-424
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• 2014

본 논문에서는 HFNS(high fanout net synthesis) 기법들 중에서 실제 현장에서는 주로 사용되고 있는 버퍼 삽입 방법을 이용한 기법에 대해서 제안하였다. 먼저 HFNS를 수행하는데 있어서 고려해야할 사항들과 HFNS수행 방법들에 대해서 세부적인 기술들을 제안하였고, HFNS 수행 이후의 후처리 과정에서 수행해야할 기법들에 대해서도 제안하였다. 버퍼 삽입 기반의 HFNS는 이미 널리 사용되는 방법인데 본 논문은 주로 ASIC 및 SoC 상용 작업 현장에서 사용될 수 있는 실전적인 기법들을 대상으로 하였다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.929-936
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• 2022

In the U.S., the state, local, tribe, and territorial governments seek funding from the federal government through the Public Assistance program to carry out these recovery works. In this paper historic public assistance data between 1998 and 2021 have been analyzed to derive several insights such as: types of disasters causing the most damage, states requiring more support, net present value of the federal expense etc. This paper has found that the states requiring more support from the federal government are not always the states suffering the maximum losses from the disasters. It has also found that the net present value of the federal expense between 1998 and 2020 to restore, repair, reconstruct, or replace disaster damaged roads and bridges across the U.S. is $15 billion in 2021 values. Moreover, this paper has tested the correlation between the states' public assistance funds requirements and the existing condition and performance of roads and bridges as revealed by the American Society of Civil Engineer's infrastructure grade card. It has found a weak correlation between these two. The outcomes of this paper can be used by the decision makers to analyze the viability of any possible alternative to the exiting public assistance program. The insights can also help in better decision making in pre-disaster preparation and post-disaster funds allocation.

• Korean Journal of Radiology
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• 제19권6호
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• pp.1066-1076
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• 2018

Objective: The reliability of size measurements of liver metastases from neuroendocrine tumors (NETs) on contrast-enhanced computed tomography (CT) phases made by different readers may be hampered due to transient, variable rim enhancement in arterial phase (AP) or portal venous phase (PVP) images. We aimed to assess the reliability of tumor size measurements in pre- and post-contrast scans. Materials and Methods: The study coordinator selected target lesions according to Response Evaluation Criteria in Solid Tumors 1.1 guidelines in 44 consecutive patients with pathologically confirmed NET liver metastases. Two blinded readers measured the longest diameters of target lesions on pre-contrast, AP, and PVP images twice with a 4-week interval. Inter- and intra-observer agreements were evaluated using Bland-Altman plots and 95% limit of agreement (LOA) calculations. Results: Of the 79 target lesions (approximate mean size of 3 cm), 45 showed rim enhancement. Inter-observer agreement assessed based on LOA was highest in pre-contrast CT images (-6.1-5.7 mm), followed by PVP (-7.9-7.1 mm) and AP (-8.5-7.4 mm) images. Intra-observer agreement showed the same trend: -2.8-2.9 mm and -2.9-2.9 mm for readers 1 and 2, respectively, on pre-contrast CT, -2.8-2.9 mm and -3.0-3.2 mm, respectively, on PVP, and -3.2-4.2 mm and -3.4-3.2 mm, respectively, on AP images. Mean tumor diameters differed significantly among the phases in the following increasing order: pre-contrast CT, PVP, and AP images. Conclusion: There was better inter- and intra-observer agreement in size measurements of NET liver metastases on pre-contrast scans than on AP and PVP scans. Pre-contrast CT may be the optimal for measuring NET liver metastases if its accuracy is proven.

• 한국토양비료학회지
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• 제31권3호
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• pp.233-237
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• 1998

토양에 시용되는 각종 폐유기물들의 토양중 질소 무기화율을 알아보기 위하여 3종의 폐유기물(A:도시고형폐기물+하수슬러지, B:목재잔사, C:목재잔사+하수슬러지)를 토양에 처리한 뒤 12주 동안 $25^{\circ}C$ 호기조건에서 질소 무기화율을 조사한 결과, 초기 질산화율은 C 처리구가 다른 처리구에 비하여 높았다. 또한 무기화된 총질소량은 C 처리구에서 가장 많았으나 실험기간 동안의 질소 무기화율과 질산화율은 무처리구에서 높게 나타났다.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2293-2302
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• 2012

단일 모드 광섬유의 그룹 속도 분산과 자기 위상 변조에 의해 왜곡된 파장 분할 다중 신호의 효율적인 보상을 위한 새로운 광전송 링크 기술을 제안하였다. 제안된 전송 링크는 WDM 송신이나 수신단 근처에 광 위상 공액기(OPC; optical phase conjugator)가 위치하고 각 중계 구간의 SMF 길이와 RDPS(residual dispersion per span)가 인위적으로 분포하는 구조이다. 시스템 성능을 개선하여 유효 입사 전력 범위와 유효 전체 잉여 분산 (NRD; net residual dispersion)을 늘릴 수 있는 최적의 링크 구조는 OPC가 WDM 수신단에 가깝게 위치하고 후치 보상(postcompensation)에 의해 NRD를 결정하고 중계 구간이 증가할수록 SMF 길이와 RDPS를 점진적으로 감소시키는 링크라는 것을 확인하였다.

• 한국정보통신학회논문지
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• 제13권5호
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• pp.959-966
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• 2009

Inline 분산 제어 (DM; dispersion management)와 전체 전송로 중간에 광 위상 공액기 (OPC; optical phase conjugator)를 갖는 WDM 시스템의 전송 용량에 따른 유효 전송 거리를 살펴보았다. 그리고 후치 보상량 (postcompensation)만으로 제어되는 1 Tbps WDM 시스템에서 1 dB 눈 열림 패널티 (EOP; eye opening penalty)를 얻을 수 있는 전체 잉여 분산 (NRD; net residual dispersion)의 범위를 살펴보았다. NRD를 시스템 전송 용량과 거리에 따라 최적화시킴으로써 유효 전송 거리가 수 백 킬로미터 이상 증가되는 것을 확인하였다. 그리고 1 Tbps WDM 시스템에서 NRD가 +17 ps/nm로 결정되면 최대 전송 거리를 얻을 수 있고, 특히 장거리 1 Tbps WDM 전송에서 유효 NRD 범위는 양의 값 내에서 결정되어야 하는 것을 확인하였다.

• 한국항행학회논문지
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• 제14권5호
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• pp.668-676
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• 2010

광 위상 공액기 (OPC; optical phase conjugator)가 단일 모드 광섬유 (SMF; single mode fiber)로 이루어진 전체 전송 거리 1000 km의 50 km 간격으로 250 km부터 750 km까지 존재하는 광전송 랭크에 inline 분산제어 (DM; dispersion management)를 통해 $24{\times}40$ Gbps WDM 채널의 신호 왜곡을 보상하기 위한 최적의 전체 잉여 분산 (NRD; net residual dispersion)을 OPC 위치별로 도출하였고, 최적 NRD가 적용된 경우의 WDM 채널의 성능 개선 정도를 NRD = 0 ps/nm로 고정된 전송 링크에서의 수신 성능과 비교하였다. 최적 NRD는 OPC가 전체 전송 거리의 중간인 500km로부터 이동된 정도에 따라 결정되어야 하고, 최적 NRD의 결정과 적용에 있어 OPC가 500km로부터 수신부쪽으로 이동되는 경우보다 송신부쪽으로 이동되는 경우가 더욱 안정적이고 효과적임을 확인하였다. 또한 0 ps/nm로 NRD가 고정된 전송 랭크에 비해 최적 NRD로 셜계된 전 송 랭크에서의 WDM 채널의 눈 열림 패널티 (EOP; eye opening penalty)가 OPC 위치에 따라 1.5 dB부터 3dB까지 개선되는 것을 확인하였다.