• Journal of Gastric Cancer
• /
• v.11 no.1
• /
• pp.23-30
• /
• 2011

Purpose: ${\alpha}$-fetoprotein (AFP)-producing gastric cancer is a rare tumor with high rates of liver metastasis and a poor prognosis. Many studies have been performed but there have been no comprehensive investigations of the clinicopathological and prognosis. Materials and Methods: Six hundred ninety four patients with gastric cancer who underwent a curative gastric resection in Hanyang University Hospital from February 2001 to December 2008 were evaluated retrospectively after excluding active or chronic hepatits, liver cirrhosis and preoperative distant metastasis. Among them, thirty five patients had an elevated serum level of AFP (>7 ng/ml) preoperatively. The clinicopathological features of AFP-producing gastric cancer were analyzed. Results: There was poorer differentiation, a higher incidence of lymph node metastasis, more marked lymphatic and vascular invasion in the AFP-positive group than in the AFP-negative group. The 5-year survival rate of the AFP-positive group was significantly poorer than that in the AFP-negative group (66% vs. 80%, P=0.002). A significantly higher incidence of liver metastasis was observed in the AFP-positive group than in the AFP-negative group (14.3% vs. 3.6%, P=0.002) with a shorter median time period from the operation to the metachronous liver metastasis (3.7 months vs. 14.1 months, P=0.043). Multivariate survival analysis revealed the depth of invasion, degree of lymph node metastasis and AFP-positivity to be the independent prognostic factors. Conclusions: AFP-producing gastric cancers have an aggressive behavior with a high metastatic potential to the liver. In addition, their clinicopathological features are quite different from the more common AFP-negative gastric cancer.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.12
• /
• pp.98-106
• /
• 2013

The duty-cycle synchronization among mobile sensor nodes with energy-harvesting is very important. The nodes should keep their duty-cycle same to others as much as possible because they have to cooperate each other and to consume energy efficiently. The distribution of node position in network affects not only node connectivity but also the active time of synchronized nodes, and it relates to network life-time finally. In this paper, we introduce a network topology change algorithm (TCA) for energy-harvesting mobile sensor networks based on self-synchronized duty-cycling. The algorithm tries to change a network topology into a balanced topology where the mobile sensor nodes are unified according to the density of the number of nodes. For TCA, both fluid flow algorithm and flock dispersion algorithm are proposed and they are evaluated through the simulation in agent based modeling language. TCA is applied to the energy-harvesting mobile sensor networks to improve the synchronization of duty-cycle and to reduce the variation of energy consumption among nodes.

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

• Smart Structures and Systems
• /
• v.6 no.8
• /
• pp.939-951
• /
• 2010

A low-cost wireless sensor network (WSN) solution with highly expandable super and simple nodes was developed. The super node was designed as a sensing unit as well as a receiving terminal with low energy consumption. The simple node was designed to serve as a cheaper alternative for large-scale deployment. A 12-bit ADC inputs and DAC outputs were reserved for sensor boards to ease the sensing integration. Vibration and thermal field tests of the Chi-Lu Bridge were conducted to evaluate the WSN's performance. Integral acceleration, temperature and tilt sensing modules were constructed to simplify the task of long-term environmental monitoring on this bridge, while a star topology was used to avoid collisions and reduce power consumption. We showed that, given sufficient power and additional power amplifier, the WSN can successfully be active for more than 7 days and satisfy the half bridge 120-meter transmission requirement. The time and frequency responses of cables shocked by external force and temperature variations around cables in one day were recorded and analyzed. Finally, guidelines on power characterization of the WSN platform and selection of acceleration sensors for structural health monitoring applications were given.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38B no.6
• /
• pp.485-491
• /
• 2013

Recently, with the proliferation of social network services, users and many companies hope that their information spread more faster. In order to study the information diffusion in the social networks, many algorithms such as greedy algorithm and heuristic algorithm have been proposed. However, the greedy algorithm is too complicated to use in real-life social network, and the heuristic algorithms have been studied under the uniform distribution of diffusion probability, which is different from the real social network property. In this paper, we propose an heuristic information diffusion maximization algorithm based on diffusion probability and node degree. For performance evaluation, we use real social network database, and it is verified that our proposed algorithm activates more active nodes than existing algorithms, which enables faster and wider information diffusion.

• The KIPS Transactions:PartD
• /
• v.11D no.2
• /
• pp.351-360
• /
• 2004

Most mobile agents are migrated to many mobile agent systems by the sequential node migration method. However. in this case, if some problems such as host's fault or obstacle etc. happened, mobile agent falls infinity walt or orphan states. Therefore, it is difficult to get an expectation effect as use of other distribution technologies because the required time for networking between nodes increases. And so, many researches have been performed to solve this problems. However, most of methods decide node migration based on passive routing table or detour hosts which have some problems. Actually, the researches for reducing the total required time for networking are insufficient yet. In this paper, to reduce the required time for networking of mobile agent we design an active routing table based on the information of implemented objects which are registered in the meta-table of naming agent. And also, for user's keyword, we propose an replication model that replicates many agent object according to the information and number of object references corresponding to meta-table. Replicated objects are migrated to mobile agent systems in parallel and it provides minimized required time for networking.

• Proceedings of the KIEE Conference
• /
• 2004.11b
• /
• pp.190-193
• /
• 2004

Optimal Power Flow (OPF) is becoming more and more important in the deregulation environment of power pool and there is an urgent need of faster solution technique for on-line application. So this paper presents parallel genetic algorithm-tap search for the solution of the OPF. The control variables modeled unit active power outputs, generator-bus voltage magnitudes and transformer-tap settings. A number of functional operating constraints, such as branch flow limits, load bus boltage magnitude limits and generator reactive capabilities are included as penalties in the fitness function. In parallel GA-TS, GA operators are executed for each process. If best fitness of the GA is not changed for several generations, TS operators are executed for the upper three populations to enhance the local searching capabilities. With migration operation, best string of each node is transferred to the neighboring node after predetermined iterations are executed. For parallel computing, we developed a PC-cluster system consisting of 8 PCs. Each PC employs the 2 GHz Pentium IV CPU and is connected with others through ethernet switch based fast ethernet. To show the usefulness of the proposed method, developed algorithm has been tested and compared on an IEEE 30-bus system in the reference paper. From the simulation results, we can find that the proposed algorithm is efficient for the OPF.

• Journal of IKEEE
• /
• v.23 no.3
• /
• pp.858-864
• /
• 2019

A clock system is proposed to eliminate data loss due to frequency difference between sensor nodes in a sensor utility network. The proposed clock system for each sensor node consists of a bust clock-data recovery (CDR) circuit, a digital phase-locked loop outputting a 32-phase clock, and a digital frequency synthesizer using a programmable open-loop fractional divider. A CMOS oscillator using an active inductor is used instead of a burst CDR circuit for the first sensor node. The proposed clock system is designed by using a 65 nm CMOS process with a 1.2 V supply voltage. When the frequency error between the sensor nodes is 1%, the proposed burst CDR has a time jitter of only 4.95 ns with a frequency multiplied by 64 for a data rate of 5 Mbps as the reference clock. Furthermore, the frequency change of the designed digital frequency synthesizer is performed within one period of the output clock in the frequency range of 100 kHz to 320 MHz.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.21 no.3
• /
• pp.67-74
• /
• 2011

In this paper, we presented a dynamic cyber attack tree which can describe an attack scenario flexibly for an active cyber attack model could be detected complex and transformed attack method. An attack tree provides a formal and methodical route of describing the security safeguard on varying attacks against network system. The existent attack tree can describe attack scenario as using vertex, edge and composition. But an attack tree has the limitations to express complex and new attack due to the restriction of attack tree's attributes. We solved the limitations of the existent attack tree as adding an threat occurrence probability and 2 components of composition in the attributes. Firstly, we improved the flexibility to describe complex and transformed attack method, and reduced the ambiguity of attack sequence, as reinforcing composition. And we can identify the risk level of attack at each attack phase from child node to parent node as adding an threat occurrence probability.

• Journal of KIISE:Information Networking
• /
• v.32 no.2
• /
• pp.167-179
• /
• 2005

In hierarchical Mobile IPv4 Networks the highest FA(Foreign Agent) may experience serious congestion and delay since the highest FA plays a role of CoA(Care of Address) for all mobile nodes in the domain, In this paper, we propose mechanism called 'HRFA(Hierarchical Root Foreign Agent)', which distributes the load imposed on the highest FA. In the proposed HRFA scheme, multiple HRFAs are selected to provide the similar service that is provided by the highest FA. According to which entity determines HRFAs, HRFA scheme is categorized into 'Active' and 'Passive' approaches. HRFA scheme is further categorized into 'All MN(Mobile Node)s' and 'New MNs' approaches, depending on which mobile nodes are assigned to a newly elected HRFA. Through a course of simulations, we investigate the performance of 4 possible combinations of HRFA schemes. We also compare the performance of the proposed HRFA schemes with the LMSP(Local Multicast Service Provider) scheme, which is a scheme to distribute the load of FA for multicast service in hierarchical wireless network domain. The simulation results show that the Passive & New MN approach performs best with respect to both the overhead and the load balancing.