• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.4061-4063
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• 2015

Background: To evaluate pathological features of head and neck squamous cell carcinoma (HNSCC) and to compare these pathological features in patients younger and older than 40 years. Materials and Methods: All resection specimens of HNSCC between 2010 and 2013 evaluated. Tumor characteristics - grade, location (site) cervical node status, alongwith presence or absence of extranodal extension, lymphovascular invasion, gender and age - were extracted from surgical pathology reports. Results: Among these n=19 patients (21.8%) were 40 years or younger and n=68 patients (78.2%) were above 40 years of age. The mean age was 34 (20-40 years) in the younger group and 56 (42-86) in the older group. The most common location of HNSCC in both groups was the oral cavity. The analysis of histopathological features including grade of tumor, tumor size, extranodal extension and comparison between two groups do not show any significant difference. Conclusions: There are no specific pathological characteristics of HNSCC in young patients. An interesting observation is that exposure to expected risk factors is similar in both groups, in younger patients they have less time to act and yet tumors are the same in terms of tumor size, lymph node status and lymphovascular invasion. Therefore further research is recommended to look for potentiating factors.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.5
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• pp.578-587
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• 2003

The DSTM (Dual Stack Transition Mechanism), one of tunneling mechanism, is considered as the best solution in IPv4/IPv6 transition recently. The DSTM provides a method to assure IPv4/v6 connectivity based on 4over6 (IPv4-over-IPv6) tunneling and temporal allocation of a global IPv4 address to a host requiring such communication. A TEP (Tunnel End Point) operates as a border router between IPv6 domain and IPv4 Internet, which performs encapsulation and decapsulation of 4over6 tunneling packets to assure hi-directional forwarding between both networks. In this paper, we analyze basic standards of the IPv6 protocol. And, we design and implement a DSTM TEP daemon block. The TEP daemon analyzes a fevers tunneling packet that is forwarded by the DSTM node, establishes the TEP's 4over6 interface, and supplies communication between a DSTM and a IPv4-only node. Finally, we construct a DSTM testbed and measure performance of the DSTM TEP. Our observation results show that performance of TEP supports the DSTM service.

• Archives of Plastic Surgery
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• v.40 no.3
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• pp.198-202
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• 2013

Background Marjolin's ulcer is known to present a high proportion of recurrence and poor prognosis compared to other kinds of skin cancer. Based on our experience, Marjolin's ulcer patients who have received reconstructive surgery present a higher proportion of recurrence when there was disturbed wound healing after surgery. The impact of disturbed wound healing after surgery on the prognosis was examined in this study. Methods A retrospective study was carried out on 26 patients who were diagnosed with Marjolin's ulcer and received surgery in this hospital from 1996 to 2011. Histologic grading, lymph node metastasis at diagnosis, and the wound healing process were evaluated and chi-squared analysis applied in order to determine the correlation with recurrence. Results The proportion of recurrence increases in patients with a low histologic grade or lymph node metastasis at diagnosis. The proportion of recurrence is even higher when the problem occurs during the wound healing process after surgery. Conclusions Disturbed wound healing after surgery could be used as a sign to quickly identify the recurrence of carcinoma. Therefore, in the event a problem occurs in the wound healing process after surgery, one should keep in mind that this could be a sign of the possibility of recurrence and proceed with careful observation and active diagnosis through additional physical examinations, general X-ray tests, computed tomographys, magnetic resonance imagings, and so on, to obtain an early diagnosis of recurrence.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.1-18
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• 2020

For the large deformation of shear walls under vertical and horizontal loads, there are difficulties in obtaining accurate simulation results using the response analysis method, even with fine mesh elements. Furthermore, concrete material nonlinearity, stiffness degradation, concrete cracking and crushing, and steel bar damage may occur during the large deformation of reinforced concrete (RC) shear walls. Matrix operations that are involved in nonlinear analysis using the traditional finite-element method (FEM) may also result in flaws, and may thus lead to serious errors. To solve these problems, a planar four-node element was developed based on vector mechanics. Owing to particle-based formulation along the path element, the method does not require repeated constructions of a global stiffness matrix for the nonlinear behavior of the structure. The nonlinear concrete constitutive model and bilinear steel material model are integrated with the developed element, to ensure that large deformation and damage behavior can be addressed. For verification, simulation analyses were performed to obtain experimental results on an RC shear wall subjected to a monotonically increasing lateral load with a constant vertical load. To appropriately evaluate the parameters, investigations were conducted on the loading speed, meshing dimension, and the damping factor, because vector mechanics is based on the equation of motion. The static problem was then verified to obtain a stable solution by employing a balanced equation of motion. Using the parameters obtained, the simulated pushover response, including the bearing capacity, deformation ability, curvature development, and energy dissipation, were found to be in accordance with the experimental observation. This study demonstrated the potential of the developed planar element for simulating the entire process of large deformation and damage behavior in RC shear walls.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.40-46
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• 2011

Wireless Sensor Networks(WSNs) have shown a lot of good outcomes in providing a various functions depending on industrial expectations by deploying ad-hoc networking with helps of light loaded and battery powered sensor nodes. In particular, it is strongly requested to develop an algorithm of cross-layer control between 2-layer and 3-layer to deriver the sensing data from the end node to the sink node on time. In this paper, based on the above observation we have proposed an IEEE802.15.4 based self priority routing scheme under UC Berkely TinyOS platform. The proposed beacon based priority routing (BPR) algorithm scheme utilizes beacon periods in sending message with embedding the high priority data and thus provides high quality of service(QoS) in the given criteria. The performance measures are the packet Throughput, delivery, latency, total energy consumption. Simulation results under TinyOS Simulator(TOSSIM) have shown the proposed scheme outcome the conventional Ad hoc On-Demand Distance Vector(AODV) Routing.

• The Journal of Korean Institute of Information Technology
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• v.17 no.9
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• pp.19-30
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• 2019

Photovoltaic power generation requires MPPT algorithm to track stable and efficient maximum power output power point according to external changes such as solar radiation and temperature. This study implemented a model that could track MPP more quickly than original MPPT algorithm using artificial neural network. The proposed model finds the current and voltage of MPP using the original MPPT algorithm for various combinations of insolation and temperature for training data of artificial neural networks. The acquired MPP data was learned using the input node as insolation and temperature and the output node as the current and voltage. The Experiment results show tracking time of the original algorithms P&O, InC and Fuzzy were respectively 0.428t, 0.49t and 0.4076t for the 0t~0.3t range, and MPP tracking time of the proposed model was 0.32511t and it is 0.1t faster than the original algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.27 no.1
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• pp.103-108
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• 2023

We study the problem of selecting a subset of sensor nodes in sensor networks in order to maximize the performance of parameter estimation. To achieve a low-complexity sensor selection algorithm, we propose a greedy iterative algorithm that allows us to select one sensor node at a time so as to maximize the log-determinant of the inverse of the estimation error covariance matrix without resort to direct minimization of the estimation error. We apply QR factorization to the observation matrix in the log-determinant to derive an analytic selection rule which enables a fast selection of the next node at each iteration. We conduct the extensive experiments to show that the proposed algorithm offers a competitive performance in terms of estimation performance and complexity as compared with previous sensor selection techniques and provides a practical solution to the selection problem for various network applications.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.122.2-122.2
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• 2011

For more than a decade, NEA (Near-Earth Asteroid) survey teams equipped with 1 meter-class telescopes discovered thousands of NEAs in the northern sky. As of August 2011, some 8,200 NEAs have been cataloged, yet only five percent of them has been investigated for their physical and chemical properties. In order to improve current situation, we propose a deep ecliptic survey utilizing KMTNet, for detection and characterization of NEAs in the southern sky. Thanks to the wide-field capability (four square degrees) of the telescopes, we will be able to considerably expand the search volume carrying out precision photometry down to 21.5th magnitude. We plan to focus our survey on opposition and two "sweet spots" in the ecliptic belt. Since SDSS colors characterize mineralogical properties of NEAs, g', r', i', z' filters will be employed. Based on the round-the-clock observation, we will study their rotational properties; for multiple systems, mass, density and other physical parameters can be obtained. We plan to maintain a dedicated database of the physical and mineralogical properties of NEAs. With this archive, it is expected that our understanding on the population will see a drastic change. We also plan to participate in the GAIA Follow-Up Network for ground based observation of the Solar System Objects (GAIA-FUN-SSO). The follow- up astrometry will be performed upon alerts issued by the GAIA-FUN-SSO Central Node in France.

• Radiation Oncology Journal
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• v.1 no.1
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• pp.111-118
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• 1983

To evaluate natural history of ovarian dysgerminoma and role of radiation therapy in treatment of ovarian dysgerminoma, retrospective study was carried out in 5 nonirradiated cases and 20 irradiated cases. Conclusions are as follows: 1. Radiation therapy is essential in treatment of ovarian dysgerminoma. 2. Even in stage 1 a, significant recurrence rate is expected in surgery only group. 3. Even in recurrent cases, if adequate radiotherapy is given in stage 1-3, we can predict near complete curability and in stage 4, we can get considerable benefit. 4. Dysgerminoma beyond stage 2 is highly fatal without radiotherapy. 5. Involved field irradiation including whole abdomen and booster RT on bulky tumor area is sufficient in radiotherapy of stage 1, 2, 3, without paraaortic node involvement. Further mediastinal and supraclavicular irradiation is indicated in stage 4 or stage 1, 2, 3, with paraaortic involvement. 6. If bilateral salphingoophorectomy was done. Elective irradiation is recommended in any condition because preservation of ovarian function is not further needed. 7. In cases of small encapsulated stage 1a, We can delay post op. RT under close observation in order to preserve fertility.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.154-157
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• 2000

Distributed piezoelectric sensor and actuator system has been designed for the active vibration control of shell structure. PVDF is used for the materials of sensor/actuator. To prevent the adverse effect of spillover, distributed modal sensor/actuator system is established. Although shell structure is three-dimensional structure, the PVDF sensor/actuator system can be treated as two-dimensional Finite element programs are developed to consider curved structures having PVDF modal sensor/actuator. The nine-node Mindlin shell element with five nodal degree of freedoms is used for finite element discretization. The electrode patterns and lamination angle of PVDF sensor/actuator are optimized to design the modal sensor/actuator system Genetic algorithm is used for optimization. Sensor is designed to minimize the observation spillover, and actuator is designed to minimize the system energy of the control modes under a given initial condition. Modal sensor/actuator for the first and second modes of singly curved cantilevered shell structure are designed using mentioned methods. Discrete LQG method is used as a control law. Experimental demonstrations of the active vibration control with designed sensor/actuator system have been performed successfully.