• 한국군사과학기술학회지
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• 제13권1호
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• pp.30-35
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• 2010

As of today, Frequency Hopping techniques are widely used for over-channel interference and anti-jamming communication systems. In this paper, analysis the performance of robustness on the focus of some general jamming channel. In FH/SS systems, usually SFH(Slow Frequency Hopping) and FFH(Fast Frequency Hopping) are took up on many special communication systems, the SFH, FFH are also combined with a channel diversity algorithm likes NED(Normalized Envelop Detection), EGC(Equal Gain Combines) and Clipped Combines to overcome jammer's attack. This paper propose Adaptive-NED and shows A-NED will be worked well than the others in the some general jamming environments.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2006년도 춘계학술발표회 논문집
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• pp.305-309
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• 2006

SAR (Synthetic Aperture Radar) technology, which is not influenced by cloud cover because of using electromagnetic wave of long wavelength, has an advantage in mapping the earth. NASA, recognizing these strong points of SAR, launched SRTM (Shuttle Radar Topography klission), and acquired the topographic information of the earth. SRTM and NED (National Elevation Data) of USGS were used for the research and vegetation height map was produced through differentiating the two data. Correlation between SRTM-NED and planting year was analyzed to see the relationship. Strong correlation was detected and it shows the feasibility of estimating timber age and eventually creating timber age map from SRTM-NED. Additional analyses were conducted to check if the linearity is influenced by regional characteristics and forest uniformity. As results, the correlation between SRTM-NED and timber age is influenced by roughness of the terrain. Overall, this paper shows that timber age estimation using SRTM and NED can be sufficiently practical.

• International Journal of Computer Science & Network Security
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• 제23권2호
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• pp.126-132
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• 2023

Web technology is evolving with the passage of time, from a single node server to high availability and then in the form of Kubernetes. In recent years, the research community have been trying to provide high availability in the form of multi master cluster with a solid election algorithm. This is helpful in increasing the resources in the form of pods inside the worker node. There are new impact of known DDoS attack, which is utilizing the resources at its peak, known as Yoyo attack. It is kind of burst attack that can utilize CPU and memory to its limit and provide legit visitors with a bad experience. In this research, we tried to mitigate the Yoyo attack by introducing a firewall at load-balancer level to prevent the attack from going to the cluster network.

• Journal of Gastric Cancer
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• 제19권1호
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• pp.121-131
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• 2019

Purpose: The significance of neuroendocrine differentiation (NED) in gastric carcinoma (GC) is controversial, leading to ambiguous concepts in traditional classifications. This study aimed to determine the prognostic threshold of meaningful NED in GC and clarify its unclear features in existing classifications. Materials and Methods: Immunohistochemical staining for synaptophysin, chromogranin A, and neural cell adhesion molecule was performed for 945 GC specimens. Survival analysis was performed using the log-rank test and univariate/multivariate models with percentages of NED ($P_{NED}$) and demographic and clinicopathological parameters. Results: In total, 275 (29.1%) cases were immunoreactive to at least 1 neuroendocrine (NE) marker. GC-NED was more common in the upper third of the stomach. $P_{NED}$, and Borrmann's classification and tumor, lymph node, metastasis stages were independent prognostic factors. The cutoff $P_{NED}$ was 10%, beyond which patients had significantly worse outcomes, although the risk did not increase with higher $P_{NED}$. Tumors with ${\geq}10%$ NED tended to manifest as Borrmann type III lesion with mixed/diffuse morphology and poorer histological differentiation; the NE components in this population mainly grew in insulae/nests, which differed from the predominant growth pattern (glandular/acinar) in GC with <10% NED. Conclusions: GC with ${\geq}10%$ NED should be classified as a distinct subtype because of its worse prognosis, and more attention should be paid to the necessity of additional therapeutics for NE components.

• 대한토목학회논문집
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• 제26권1D호
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• pp.203-209
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• 2006

SAR (Synthetic Aperture Radar) 는 긴 파장대의 전자기파를 사용하므로 날씨의 영향을 받지 않는다. 따라서 지구를 관측하는데 있어서 잇점을 갖고 있으므로 NASA는 SRTM (Shuttle Radar Topography Mission) 미션수행을 통해 지형정보를 획득하였다. 본 논문에서는 SRTM 데이터와 USGS의 NED (National Elevation Datasets) 데이터를 사용하였으며 두 데이터를 차분함으로써 식생수고도(vegetation height map)를 얻었다. 또한 차분값과 shape 파일에 포함된 식수년도의 비교를 통해 상관관계여부를 판단하고자 했다. 본 논문에서는 회귀분석을 통해 차분데이터와 식수년도 사이의 큰 상관관계가 존재함을 확인할 수 있었으며 결국 수령추정과 수령정보의 맵핑이 가능함을 보였다. 추가적으로 지역별 지형특성, 숲의 균일도 등에 의해 선형성이 영향을 받는지 관찰하였다. 결론적으로 본 논문에서는 차분영상으로부터 얻은 식생수령추정 모델이 지역의 기복의 영향을 받지만 여전히 높은 상관관계를 가지므로 충분히 유용할 수 있다는 것을 확인할 수 있었다.

• Communications for Statistical Applications and Methods
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• 제5권2호
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• pp.517-529
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• 1998

When the sample size is small the robust minimum Hellinger distance (HD) estimator can have substantially poor relative efficiency at the true model. Similarly, approximating the exact null distributions of the ordinary Hellinger distance tests with the limiting chi-square distributions can be quite inappropriate in small samples. To overcome these problems Harris and Basu (1994) and Basu et at. (1996) recommended using a modified HD called penalized Hellinger distance (PHD). Lindsay (1994) and Basu et al. (1997) showed that another density based distance, namely the negative exponential disparity (NED), is a major competitor to the Hellinger distance in producing an asymptotically fully efficient and robust estimator. In this paper we investigate the small sample performance of the estimates and tests based on the NED and penalized NED (PNED). Our results indicate that, in the settings considered here, the NED, unlike the HD, produces estimators that perform very well in small samples and penalizing the NED does not help. However, in testing of hypotheses, the deviance test based on a PNED appears to achieve the best small-sample level compared to tests based on the NED, HD and PHD.

• 한국측량학회지
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• 제28권4호
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• pp.431-439
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• 2010

교차간섭기법은 ERS-2와 Envisat SAR 데이터를 이용하여 긴 기선거리를 지니면서도 양질의 간섭도를 제작할 수 있다. 또한 긴 기선거리에 의해서 고도에 대한 프린지 변화율이 약 5m 내외로 계산되며 이는 매우 정밀한 DEM생성을 가능하게 한다. 본 연구에서는 ERS-2와 Envisat 교차 간섭기법으로부터 정밀한 DEM을 추출하는 효율적인 방안을 제안하였으며 경사가 매우 완만한 알라스카지역에서 교차간섭기법으로 제작된 CInSAR(Cross-Interferometry SAR) DEM과 기존에 존재하는 NED(National Elevation Dataset) DEM을 비교하였다. 연구 결과 차분 간섭도 생성과정에서 NED DEM 오차라고 생각되는 부분이 발견되었으며 이 부분에 대한 CInSAR DEM과의 고도 차이에 대한 표준편차는 2.63m로 계산되었다. 하지만 전체지역에 대해서는 NED DEM과 CInSAR DEM의 고도값 차이에 대한 표준편차는 약 1m로 NED DEM과 매우 유사한 값이 계산되었다. 이는 연구대상 지역이 매우 편평한 지형으로 양질의 DEM이 구축되어 있으므로 매우 유사한 값이 계산된 것으로 판단된다. 하지만 두 DEM에 대한 공간주파수 분석을 하였을 경우 CInSAR DEM은 약 0.08 rad/m(약 40m) 보다 고주파영역에서도 높은 파워 스펙트럼 값을 지닌 반면 NED DEM은 그렇지 못하였다. 결과적으로 16m로 해상도로 구축된 CInSAR DEM의 경우 NED DEM보다 약 2.5배 공간해상도가 높아졌으며 경사가 심하지 않은 지역에서도 정밀한 DEM이 생성되었다.

• 전기학회논문지
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• 제62권5호
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• pp.639-642
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• 2013

In this paper, proposed NED(nuclear event detectors) for detection of a transient radiation. Nuclear event detector was blocked of power temporary for defence of critical damage at a electric device when a induced transient radiation. Conventional NED consist of BJT, resistors and capacitors. The NED supply voltage of 5V and MCM(Multi Chip Module) structures. The proposed NED were designed for low supply voltage using 0.18um CMOS process. The response time of proposed NED was 34.8ns. In addition, pulse radiation experiments using a electron beam accelerator, the output signal has occurred.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.161-166
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• 2021

The term parking management system usually refers to the custom built hardware intensive systems installed in building and malls. However, there are many places where such expensive solutions cannot be installed due to various reasons, like cost and urgent/temporary setup requirements. This project focuses on developing a parking management system based on image processing to detect vacant parking slot in an area where automated systems are not installed. Camera images of the parking area are subjected to image processing algorithm which marks virtual slots in the area and extracts occupancy information to guide the incoming drivers about availability and position of vacant spaces. The application consists of two interfaces: one for the guidance of the incoming drivers and the other one for the administrator. The later interface also informs the administrator if a car is not parked properly in the virtual slot. This parking system would reduce the stress and time wastage associated with car parking and would make the management of such areas less costly.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.223-229
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• 2022

LinkedIn is one of the most job hunting and career-growing applications in the world. There are a lot of opportunities and jobs available on LinkedIn. According to statistics, LinkedIn has 738M+ members. 14M+ open jobs on LinkedIn and 55M+ Companies listed on this mega-connected application. A lot of vacancies are available daily. LinkedIn data has been used for the research work carried out in this paper. This in turn can significantly tackle the challenges faced by LinkedIn and other job posting applications to improve the levels of jobs available in the industry. This research introduces Text Processing in natural language processing on datasets of LinkedIn which aims to find out the jobs that appear most in a month or/and year. Therefore, the large data became renewed into the required or needful source. This study thus uses Multinomial Naïve Bayes and Linear Support Vector Machine learning algorithms for text classification and developed a trained multilingual dataset. The results indicate the most needed job vacancies in any field. This will help students, job seekers, and entrepreneurs with their career decisions