• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.23-34
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• 2010

As the number of user increases according to the improvement of the network, the multi-thread schemes are used to process the service requests of several users who are connected simultaneously. The static thread pool scheme has the problem of occupying a static amount of system resources. On the other hand, the dynamic thread pool scheme can control the number of threads according to the users' requests. However, it has disadvantage that this scheme cannot react to the requests which are larger than the maximum value assigned. In this paper, a web server using a learning-based dynamic thread pool scheme is suggested, which will be running on a server programming of a multi-thread environment. The suggested scheme adds the creation of the threads through the prediction of the next number of periodic requests using Auto Regressive scheme with the web server apache worker MPM (Multi-processing Module). Unlike previous schemes, in order to set the exact number of the necessary threads during the unchanged number of work requests in a certain period, K-Nearest Neighbor algorithm is used to learn the number of threads in advance according to the number of requests. The required number of threads is set by comparing with the previously learned objects. Then, the similar objects are selected to decide the number of the threads according to the request, and they create the threads. In this paper, the response time has decreased by modifying the number of threads dynamically, and the system resources can be used more efficiently by managing the number of threads according to the requests.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.3
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• pp.140-148
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• 2009

Recent advances in communication and multimedia technologies make it possible to provide video-on-demand(VOD) services and people can access video servers over the Internet at any time using their electronic devices, such as PDA, mobile phone and digital TV. Each device has different processing capabilities, energy budgets, display sizes and network connectivities. To support such diverse devices, multiple versions of videos are needed to meet users' requests. In general cases, VOD servers cannot store all the versions of videos due to the storage limitation. When a device requests a stored version, the server can send the appropriate version immediately, but when the requested version is not stored, the server first converts some stored version to the requested version, and then sends it to the client. We call this conversion process transcoding. If transcoding occurs frequently in a VOD server, the CPU resource of the server becomes insufficient to response to clients. Thus, to admit as many requests as possible, we need to maximize the CPU availability. In this paper, we propose a new algorithm to select versions from those stored on disk using a branch and bound technique to maximize the CPU availability. We also explore the impact of these storage management policies on streaming to heterogeneous users.

• IMMUNE NETWORK
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• v.5 no.3
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• pp.163-171
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• 2005

Background: To perform the successful dendritic cell-based cancer immunotherapy one of the main issues to be solved is the source of antigen for DC pulsing. Limitations occur by using auto-tumor lysate due to the difficulties obtaining enough tumor tissue(s) quantitatively as well as qualitatively. In this study the possibility of allogeneic tumor cell lysate as a DC pulsing antigen has been tested in mouse melanoma pulmonary me tastasis model. Methods: B16F10 melanoma cells $(1{\timeS}10^5/mouse)$ were inoculated intra venously into the C57BL/6 mouse. Therapeutic DCs were cultured from the bone marrow myeloid lineage cells with GM-CSF and IL-4 (1,000 U/ml each) for 7 days and pulsed with lysate of either autologous B16F10 (B-DC), allogeneic K1735 (C3H/He origin; K-DC) or CloneM3 (DBA2 origin; C-DC) melanoma cells for 18 hrs. Pulsed-DCs $(1{\times}10^6/mouse)_{[CGP1]}$ were injected i.p. twice with one week interval starting from the day 1 after tumor cell inoculation. Results: Without observable toxicity, allogeneic tumor cell lysate pulsed-DC induced the significantly better anti-tumor response (tumor scale: $2.7{\pm}0.3,\;0.7{\pm}0.3\;and\;0.3{\pm}0.2$ for saline, B-DC and C-DC treated group, respectively). Along with increased tumor specific lymphocyte proliferations, induction of IFN-${\gamma}$ secretion against both auto- and allo-tumor cell lysates was observed from the DC treated mice. (w/B16F10-lysate: $44.97{\pm}10.31,\;1787.94{\pm}131.18,\;1257.15{\pm}48.27$, w/CloneM3 lysate: 0, $1591.13{\pm}1.83,\;1460.47{\pm}86.05pg/ml$ for saline, B-DC and C-DC treated group, respectively) Natural killer cell activity was also increased in the mice treated with tumor cell lysate pulsed-DC ($8.9{\pm}_{[CGP2]}0.1,\;11.6{\pm}0.8\;and\;12.6{\pm}0.7%$ specific NK activity for saline, B-DC and C-DC treated group, respectively). Conclusion: Conclusively, promising data were obtained that allogeneic-tumor cell lysate can be used as a tumor antigen for DC-based cancer immunotherapy.

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.179-191
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• 2014

In this paper, a frame transmission method to make IEEE 802.15.4 nodes run at a new channel and its characteristics are studied when they experience difficulties in transmission of frames due to WiFi traffic. The researches on evaluating the interference from WiFi traffic, searching for a new channel with little interference or not, and changing the operating channel are analyzed. In an wireless channel overlapped with IEEE 802.11 network, the transmission delay of IEEE 802.15.4 frames, the collision of frames in sending IEEE 802.15.4 frames without applying CSMA-CA algorithm, and the operation of IEEE 802.11 nodes are explained. A transmission method of frames including frame-formated code blocks in order to use the rest part of collided IEEE 802.15.4 frame is proposed. In the experiments of the proposed method, it is observed that frame-formated code blocks are synchronized and received by receivers in case of collision, and then the collided positions in IEEE 802.15.4 frame and the characteristics of frame reception rate are analyzed. The experimental results show that the performance of the proposed method is improved in comparison to an existing method when we measure the time taken to send a channel change command and get the response in order to avoid the interference from WiFi traffic.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.773-780
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• 2005

Recently, the telecommunication network is in a transition toward the BcN (Broadband convergence Networks) that integrates the Internet, the telecommunication and the broadcasting. The BcN makes it possible to provide of 4he third-party application by using the Open API The Parlay X API is an example of the Open API and the Parlay X API is grafted in the Web Service and is abstracted from the Parlay API. So, the Parlay X API does not only have advantages of a Web Service, but also disadvantages of the Web Service. The main disadvantage of the Web Service is that it does not support the any QoS mechanism. In this paper, we propose the architecture that solves the reliability among the QoS issues for the Web Service. The proposed mechanism adopts the Asynchronous architecture for the reliable Web Service and improves the performance of the retransmission between the client and the server using the expected response time. We perform the performance evaluation through the simulation in older to compare with the existing mechanism. Consequently, we can confirm that the performance of the proposed mechanism performs better than the existing mechanism.

• Korean Journal of Remote Sensing
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• v.34 no.2_2
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• pp.313-326
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• 2018

This paper introduces core techniques on ship detection and tracking based on a compact HF radar platform which is necessary to establish a wide-area surveillance network. Currently, most HF radar sites are primarily optimized for observing sea surface radial velocities and bearings. Therefore, many ship detection systems are vulnerable to error sources such as environmental noise and clutter when they are applied to these practical surface current observation purpose systems. In addition, due to Korea's geographical features, only compact HF radars which generates non-uniform antenna response and has no information on target information are applicable. The ship detection and tracking techniques discussed in this paper considers these practical conditions and were evaluated by real data collected from the Yellow Sea, Korea. The proposed method is composed of two parts. In the first part, ship detection, a constant false alarm rate based detector was applied and was enhanced by a PCA subspace decomposition method which reduces noise. To merge multiple detections originated from a single target due to the Doppler effect during long CPIs, a clustering method was applied. Finally, data association framework eliminates false detections by considering ship maneuvering over time. According to evaluation results, it is claimed that the proposed method produces satisfactory results within certain ranges.

• Journal of KIISE:Databases
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• v.34 no.5
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• pp.448-464
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• 2007

Location-Based Services (LBSs) provide results to queries according to the location of the client issuing the query. In LBS, techniques such as caching and prefetching are effective approaches to reducing the data transmission from a server and query response time. However, they can lead to cache inefficiency and network overload due to the client's mobility and query pattern. To solve these drawbacks, we propose a semantic prefetching (SP) scheme using prefetching segment concept and improved cache replacement policies. When a mobile client enters a new service area, called semantic prefetching area, proposed scheme fetches the necessary semantic information from the server in advance. The mobile client maintains the information in its own cache for query processing of location-dependent data (LDD) in mobile computing environment. The performance of the proposed scheme is investigated in relation to various environmental variables, such as the mobility and query pattern of user, the distributions of LDDs and applied cache replacement strategies. Simulation results show that the proposed scheme is more efficient than the well-known existing scheme for range query and nearest neighbor query. In addition, applying the two queries dynamically to query processing improves the performance of the proposed scheme.

• IMMUNE NETWORK
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• v.6 no.2
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• pp.86-92
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• 2006

Background: Germanium compounds are increased to use in nutrient foods and medicines in terms of antibiotics to microbes, anticancer, modulation of immune system and neutralizing heavy metal toxins. Geranti Bio-Ge Yeast, containing stable organic germanium and bound to the yeast protein was developed by Geranti Pharm. LTD. and the modulation effect in the immune system was examined in vivo and in vitro. Methods: The compound, Geranti Bio-Ge Yeast, was fed to female Balb/c mice (each group has 10 mice) for 4 weeks and the yeast powder and steamed red ginseng powder were used as control during the same feeding time points. During 4 weeks there was no symptom to be considered, and after 4 weeks feeding all mice were sacrificed to check the changes of related immune cells and subsidiary responses (i.e. cell counting, FACS, MTT, LDH, PFC assay). Results: In pre-post comparison, B cell population was increased in the group of Geranti Bio-Ge Yeast in a dose dependent manner (100 to 800 mg/kg). However, the population of T cell, dendritic cell and macrophage was not comparably changed in all doses. The ability of cytokine production and proliferation was almost same level as shown in control group. In contrast, PFC assay informed that the compound increase the antibody production ability when fed over 200 mg/kg implying that the increase of PFC number might be due to the increase of B cells. Conclusion: Over the entire study, we concluded that the compound, Geranti Bio-Ge Yeast has better potential in immune response in terms of B cell proliferation than that of positive control, red ginseng, and the compound can be one of the future candidates for a new supplementary source improving immune system activity.

• IMMUNE NETWORK
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• v.13 no.2
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• pp.70-74
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• 2013

L-ascorbic acid (vitamin C) is one of the well-known antiviral agents, especially to influenza virus. Since the in vivo antiviral effect is still controversial, we investigated whether vitamin C could regulate influenza virus infection in vivo by using Gulo (-/-) mice, which cannot synthesize vitamin C like humans. First, we found that vitamin C-insufficient Gulo (-/-) mice expired within 1 week after intranasal inoculation of influenza virus (H3N2/Hongkong). Viral titers in the lung of vitamin C-insufficient Gulo (-/-) mice were definitely increased but production of anti-viral cytokine, interferon (IFN)-${\alpha}/{\beta}$, was decreased. On the contrary, the infiltration of inflammatory cells into the lung and production of pro-inflammatory cytokines, tumor necrosis factor (TNF)-${\alpha}$ and interleukin (IL)-${\alpha}/{\beta}$, were increased in the lung. Taken together, vitamin C shows in vivo antiviral immune responses at the early time of infection, especially against influenza virus, through increased production of IFN-${\alpha}/{\beta}$.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.12
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• pp.301-312
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• 2018

In industrial wireless sensor networks, the continuous object detection such as fire or toxic gas detection is one of major applications. A continuous object occurs at a specific point and then diffuses over a wide area. Therefore, many studies have focused on accurately detecting a continuous object and delivering data to a static sink with an energy-efficient way. Recently, some applications such as fire suppression require mobile sinks to provide real-time response. However, the sink mobility support in continuous object detection brings challenging issues. The existing approaches supporting sink mobility are designed for individual object detection, so they establish one-to-one communication between a source and a mobile sink for location update. But these approaches are not appropriate for a continuous object detection since a mobile sink should establish one-to-many communication with all sources. The one-to-many communication increases energy consumption and thus shortens the network lifetime. In this paper, we propose the origin-centric communication scheme to support sink mobility in a continuous object detection. Simulation results verify that the proposed scheme surpasses all the other work in terms of energy consumption.