• 한국정보통신학회논문지
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• 제18권7호
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• pp.1721-1726
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• 2014

유비쿼터스 컴퓨팅의 핵심 기술인 센서 네트워크 기술이 각광을 받으면서 다양한 종류의 센서 노드로 구성된 센서 네트워크에 대한 연구가 활발히 진행되고 있다. 센서 네트워크 어플리케이션들의 주요 트래픽 패턴은 몇몇의 센서 노드들로부터 싱크 노드로 패킷을 전송하는 타입의 단일 방향성 데이터 수집형태로 구성되어있으며 소스 노드, 중간 노드, 싱크 노드에 이르기 까지 각각 자신의 상위 노드를 곧 바로 깨움으로써 지연의 감소와 에너지 효율성을 이끌어냈다. 본 논문에서는 센서 노드의 지연 감소를 위해 2계층 클러스터 구조를 제시하고 이에 기존에 사용한 라우팅 프로토콜을 네트워크 시뮬레이션을 통해 비교 분석하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.104-111
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• 2002

A new triangular element fur the finite element analysis of plate-bending problems is presented. For the purpose of sharing the program code of 4 node plate-bending element, two nodes of the 4-node element are combined to form a triangular element. Thus, the presented element would bring about great deal of efficiency of the computer program. The proposed variable-node elements pass the patch tests, do not show spurious zero-energy modes, and do not produce shear locking phenomena. It is also shown that the elements produce reliable solutions through numerical tests for standard benchmark problems.

• Asian Pacific Journal of Cancer Prevention
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• 제14권4호
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• pp.2225-2229
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• 2013

Background: As data on the relation between obesity and lymph node ratio are missing in the literature, we here aimed to assess the impact of obesity on this parameter and other clinicopathological features of breast cancer cases and patient survival. Materials and Methods: Medical data of 646 patients, all referred to two centers in Tehran, Iran, were reviewed. Factors that showed significant association on univariate analysis were entered in a regression model. Kaplan-Meier and Cox-regression were employed for survival analysis. Results: Obesity was correlated with the expression of estrogen and progesterone receptor (p=0.004 and p=0.039, respectively), metastasis to axillary lymph nodes (p=0.017), higher lymph node rate (p<0.001) and larger tumor size (p<0.001). The effect of obesity was stronger in premenopausal women. There was no association between obesity and expression of human epidermal growth factor receptor. Three factors showed independent association with BMI on multivariate analysis; tumor size, estrogen receptor and lymph node ratio. Obesity was predictive of shorter disease-free survival with a hazard ratio of 3.324 (95%CI: 1.225-9.017) after controlling for the above-mentioned variables. Conclusions: The findings of this study support the idea that obese women experience more advanced disease with higher axillary lymph node ratio, and therefore higher stage at the time of diagnosis. Furthermore, obesity was associated with poorer survival independent of lymph node rate.

• 한국전자통신학회논문지
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• 제10권7호
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• pp.837-844
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• 2015

소셜 네트워크 연구는 단일노드와 링크에 초점이 맞추어져 있다. 하지만, 소셜 네트워크의 복잡성을 고려할 때, 특정조건을 만족하는 여러 노드에 의한 종합적인 영향을 분석하는 것이 필요하고 생각한다. 하지만, 서브 네트워크 외에는 연구가 진행되고 있지 않다. 본 논문은 여러 노드에 의한 영향 분석에 중점을 두고 있다. 이를 위하여 특정 조건을 만족하는 복수개의 노드로 구성된 그룹노드 용어를 정의한다. 그리고 그룹노드를 적용하여 소셜 네트워크를 새롭게 구성하는 방법을 제시한다. 그리고 특정 조건에 맞는 그룹노드를 구성하는 프로그램을 유전자 알고리즘을 활용하여 제작하고, 결과를 제시하였다. 본 연구가 그룹노드를 기반으로 하는 소셜 네트워크 분석의 시발점이 되기를 바란다.

• 대한두경부종양학회지
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• 제26권2호
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• pp.183-186
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• 2010

Purpose : Papillary thyroid carcinoma (PTC) is known for malignant tumor which has a favorable prognosis and long-term survival. Although the prognosis for patients with PTC is generally good, PTC tends to have highly metastatic property. The purpose of this study was to analyze the central compartment lymph node in papillary thyroid cancer with no lymph node metastasis clinically and to assess the significance of prophylactic node dissection. Methods : A retrospective review was carried out in 394 patients with PTC who underwent surgery for the period from January 2004 to December 2006. The positive rate of the lymph node metastasis was analyzed. The relations between the central compartment lymph nodes and the patients' age, gender, tumor size, exrathyroidal extension(ETE), multifocality, and bilaterality were comparatively analyzed in PTC patients with preoperative no lymph node metastasis. Results : The enrolled patients were 40 male and 354 female cases. The 118 cases of them were found to have cervical lymph node metastasis. The mean age was 46 years(range, 15-77years). Tumor size(p=0.000), ETE(p=0.001), multifocality(p=0.014), and bilaterality(p=0.001) were significantly related factors for cervical lymph node metastasis clinically in papillary thyroid cancer. However, age and gender were not significantly related with lymph node metastasis. Conclusion : Although no lymph node metastasis clinically, prophylactic neck node dissection can be performed to avoid risks of local recurrence and reoperation in the light of PTC nature. The pathological status and high positive rate of central compartment lymph node relate to tumor size and extrathyroidal extension. Close surveillance for nodal status is required in follow-up.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권9호
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• pp.3615-3638
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• 2020

Node identity authentication is an essential means to ensure the security of the Internet of Things. Existing blockchain-based IoT node authentication schemes have many problems. A heterogeneous IoT node authentication scheme based on an improved hybrid blockchain is proposed. Firstly, the hybrid blockchain model is designed to make the blockchain and IoT environment more compatible. Then the proxy node selection mechanism is intended to establish a bridge between the ordinary IoT node and the blockchain, building by calculating the trust value between nodes. Finally, based on the improved hybrid blockchain, the node authentication scheme of the model and proxy node selection mechanism establishes a secure connection for communication between nodes. Safety and performance analysis shows proper safety and performance.

• 대한두경부종양학회지
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• 제34권1호
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• pp.1-7
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• 2018

Papillary thyroid carcinoma has a good prognosis, but the frequency of locoregional lymph node metastasis is high and is known to occur stepwise fashion. Prophylactic central node dissection in papillary thyroid carcinoma is widely performed from the past. But, the pros and cons of the prophylactic central node dissection has been ongoing for a long time. In the American Thyroid Association management guideline for thyroid nodules and differentiated thyroid cancer, which is the most widely used, recommendations about prophylactic central node dissection has been changed in past ten years. In recent systematic review and meta-analysis, prophylactic central node dissection increases the rate of transient hypocalcemia and recurrent laryngeal nerve injury, but there is no difference in the frequency of permanent hypocalcemia or recurrent laryngeal nerve injury. Prophylactic central node dissection has not been shown to improve patient survival, but recurrence has been reported to decrease. According to a questionnaire survey of the members of Korean Scociety of Thyroid-Head and Neck Surgery, Korean doctors tend to perform the prophylactic central node dissection more aggressively than other countries. The reason for this is that Korea has a large number of thyroid surgeries and therefore surgeons are more experienced than other countries.

• 센서학회지
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• 제16권5호
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• pp.361-368
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• 2007

Small size real-time ECG signal analysis function by QRS-complex detection was put into sensor nodes. Wireless sensor nodes attached on the patient’s body transmit ECG data continuously in normal u-healthcare system. So there are heavy communication traffics between sensor nodes and gateways. New developed platform for real-time analysis of ECG signals on sensor node can be used as an advanced diagnosis and alarming system for healthcare. Sensor node does not need to transmit ECG data all the time in wireless sensor network and to server PC via gateway. When sensor node detects suspicion or abnormality in ECG, then the ECG data in the network was transmitted to the server PC for further powerful analysis. This system can reduce data packet overload and save some power in wireless sensor network. It can also increase the server performance.

• Steel and Composite Structures
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• 제18권5호
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• pp.1197-1214
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• 2015

There is a great difference in mechanical behavior between design model one-time loading and step-by-step construction process. This paper presents practical computational methods for simulating the structural behavior of long-span rigid steel structures during construction processes. It introduces the positioning principle of node rectification for installation which is especially suitable for rigid long-span steel structures. Novel improved nonlinear analytical methods, known as element birth and death of node rectification, are introduced based on several calculating methods, as well as a forward iteration of node rectification method. These methods proposed in this paper can solve the problem of element's 'floating' and can be easily incorporated in commercial finite element software. These proposed methods were eventually implemented in the computer simulation and analysis of the main stadium for the Universiade Sports Center during the construction process. The optimum construction scheme of the structure is determined by the improved algorithm and the computational results matched well with the measured values in the project, thus indicating that the novel nonlinear time-varying analysis approach is effective construction simulation of complex rigid long-span steel structures and provides useful reference for future design and construction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권10호
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• pp.2529-2547
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• 2012

In this paper, we use a quadrotor-based mobile sink to gather sensor data from the terrestrial deployed wireless sensor network. By analyzing the flight features of the mobile sink node, we theoretically study the flight constraints of height, velocity, and trajectory of the mobile sink node so as to communicate with the terrestrial wireless sensor network. Moreover, we analyze the data amount which the mobile sink can send when it satisfies these flight constraints. Based on these analysis results, we propose a data acquisition approach for the mobile sink node, which is discussed detailed in terms of network performance such as the transmission delay, packet loss rate, sojourning time and mobile trajectory when given the flying speed and height of the mobile sink node. Extensive simulation results validate the efficiency of the proposed scheme.