• Title/Summary/Keyword: Network Fragmentation

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From Fragmented Development to Three-Dimensional and Coordinated Development - Research on Renewal Strategies of Existing Underground Commercial Space in Harbin

  • Xue, Minghui;Su, Yiming;Hu, Jiayu
    • International Journal of High-Rise Buildings
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    • v.10 no.1
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    • pp.17-28
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    • 2021
  • In Harbin, a network of underground commercial spaces has been developed to occupy spaces that were originally created as civil defense shelters. With the gradual extension of the local metro rail system, the existing underground commercial space is no longer an isolated regional development, but a space that represents "three-dimensional city" and coordinated development taking place in many Chinese cities. Based on the analysis of the unique development process taken in underground space of Harbin, this paper summarizes three characteristics of its early model of "fragmented development" of underground space. By conducting a comprehensive field research and survey, the researchers analyzed 472 questionnaires related to the development trend, and proposed multi-level synergistic elements for the renewal and development of underground commercial space. The paper concludes by discussing the trend of "three-dimensional and collaborative development," suitable for the development needs of the new era, and the corresponding development strategies for the renewal of underground space.

Analysis on Energy Consumption Required for Building DTLS Session Between Lightweight Devices in Internet of Things (사물인터넷에서 경량화 장치 간 DTLS 세션 설정 시 에너지 소비량 분석)

  • Kwon, Hyeokjin;Kang, Namhi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.8
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    • pp.1588-1596
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    • 2015
  • In the Internet of Things (IoT), resource-constrained devices such as sensors are capable of communicating and exchanging data over the Internet. The IETF standard group has specified an application protocol CoAP, which uses UDP as a transport protocol, allows such a lightweight device to transmit data. Also, the IETF recommended the DTLS binding for securing CoAP. However, additional features should be added to the DTLS protocol to resolve several problems such as packet loss, reordering, fragmentation and replay attack. Consequently, performance of DTLS is worse than TLS. It is highly required for lightweight devices powered by small battery to design and implement a security protocol in an energy efficient manner. This paper thus discusses about DTLS performance in the perspective of energy consumption. To analyze the performance, we implemented IEEE 802.15.4 based test network consisting of constrained sensor devices in the Cooja simulator. We measured energy consumptions required for each of DTLS client and server in the test network. This paper compares the energy consumption and amount of transmitted data of each flight of DTLS handshake, and the processing and receiving time. We present the analyzed results with regard to code size, cipher primitive and fragmentation as well.

An Efficient Dissemination Protocol for Remote Update in 6LoWPAN Sensor Network (6LoWPAN상에서 원격 업데이트를 위한 효율적인 코드 전파 기법)

  • Kim, Il-Hyu;Cha, Jung-Woo;Kim, Chang-Hoon;Nam, In-Gil;Lee, Chae-Wook
    • Journal of the Institute of Convergence Signal Processing
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    • v.12 no.2
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    • pp.133-138
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    • 2011
  • In IP-based wireless sensor networks (WSNs), it might be necessary to distribute application updates to the sensor nodes in order to fix bugs or add new functionality. However, physical access to nodes is in many cases extremely limited following deployment. Therefore, network reprogramming protocols have recently emerged as a way to distribute application updates without requiring physical access to sensor nodes. In order to solve the network reprogramming problem over the air interface, this thesis presents a new scheme for new update code propagation using fragmentation scheme and network coding. The proposed code propagation method roughly shows reduced performance improvement in terms of the number of data exchange compared with the previously proposed pipelining scheme. Further, It is shows enhanced reliability for update code propagation and reduced overhead in terms of the number of data exchange. As a result, we can efficiently perform the software update from the viewpoint of speed, energy, and network congestion when the proposed code propagation system is applied. In addition, the proposed system solves overhearing problems of network coding such as the loss of original messages and decoding error using the predefined message. Therefore, our system allows a software update system to exchange reliable data in wireless sensor networks.

Analysis of Spatial Changes in the Forest Landscape of the Upper Reaches of Guem River Dam Basin according to Land Cover Change (토지피복변화에 따른 금강 상류 댐 유역 산림 경관의 구조적 변화 분석)

  • Kyeong-Tae Kim;Hyun-Jung Lee;Whee-Moon Kim;Won-Kyong Song
    • Korean Journal of Environment and Ecology
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    • v.37 no.4
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    • pp.289-301
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    • 2023
  • Forests within watersheds are essential in maintaining ecosystems and are the central infrastructure for constructing an ecological network system. However, due to indiscriminate development projects carried out over past decades, forest fragmentation and land use changes have accelerated, and their original functions have been lost. Since a forest's structural pattern directly impacts ecological processes and functions in understanding forest ecosystems, identifying and analyzing change patterns is essential. Therefore, this study analyzed structural changes in the forest landscape according to the time-series land cover changes using the FRAGSTATS model for the dam watershed of the Geum River upstream. Land cover changes in the dam watershed of the Geum River upstream through land cover change detection showed an increase of 33.12 square kilometers (0.62%) of forests and 67.26 square kilometers (1.26%) of urbanized dry areas and a decrease of 148.25 square kilometers (2.79%) in agricultural areas from the 1980s to the 2010s. The results of no-sampling forest landscape analysis within the watershed indicated landscape percentage (PLAND), area-weighted proximity index (CONTIG_AM), average central area (CORE_MN), and adjacency index (PLADJ) increased, and the number of patches (NP), landscape shape index (LSI), and cohesion index (COHESION) decreased. Identification of structural change patterns through a moving window analysis showed the forest landscape in Sangju City, Gyeongsangbuk Province, Boeun County in Chungcheongbuk Province, and Jinan Province in Jeollabuk Province was relatively well preserved, but fragmentation was ongoing at the border between Okcheon County in Chungcheongbuk Province, Yeongdong and Geumsan Counties in Chungcheongnam Province, and the forest landscape in areas adjacent to Muju and Jangsu Counties in Jeollabuk Province. The results indicate that it is necessary to establish afforestation projects for fragmented areas when preparing a future regional forest management strategy. This study derived areas where fragmentation of forest landscapes is expected and the results may be used as basic data for assessing the health of watershed forests and establishing management plans.

A Combination of PG490 and Lipopolysaccharide Induce Apoptosis through Activation of Casapase-3 and Downregulation of cIAP1 and XIAP in Human Astroglioma Cell

  • Lee, Tae-Jin;Woo, Kyung-Jin;Park, Jong-Wook;Kwon, Taeg-Kyu
    • IMMUNE NETWORK
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    • v.5 no.2
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    • pp.99-104
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    • 2005
  • Background: Malignant gliomas are the most common primary tumors in the central nervous system. Methods: We investigated the combined effect of PG490 and LPS on the induction of the apoptotic pathway in human astroglioma cells. Results: Treatment of U87 cells with combination of 50nM of PG490 and $50{\mu}g/ml$ of LPS resulted in increased internucleosomal DNA fragmentation, cleavage of PLC-${\gamma}1$, and downregulation of cIAP1 and XIAP. The combination of LPS and PG490 treatment-induced apoptosis is mediated through the activation of caspase, which is inhibited by the caspase inhibitor, z-VAD-fmk. Also, release of cytochrome c was found in PG490 and LPS-cotreated U87 cell. Conclusion: Taken together, combination of PG490 and LPS appears to be a potent inducer of apoptosis in astrogliaoma cells, and might have some benefit in the treatment of glioma patients.

The Nuclear Orphan Receptor NR4A1 is Involved in the Apoptotic Pathway Induced by LPS and Simvastatin in RAW 264.7 Macrophages

  • Kim, Yong Chan;Song, Seok Bean;Lee, Sang Kyu;Park, Sang Min;Kim, Young Sang
    • IMMUNE NETWORK
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    • v.14 no.2
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    • pp.116-122
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    • 2014
  • Macrophage death plays a role in several physiological and inflammatory pathologies such as sepsis and arthritis. In our previous work, we showed that simvastatin triggers cell death in LPS-activated RAW 264.7 mouse macrophage cells through both caspase-dependent and independent apoptotic pathways. Here, we show that the nuclear orphan receptor NR4A1 is involved in a caspase-independent apoptotic process induced by LPS and simvastatin. Simvastatin-induced NR4A1 expression in RAW 264.7 macrophages and ectopic expression of a dominant-negative mutant form of NR4A1 effectively suppressed both DNA fragmentation and the disruption of mitochondrial membrane potential (MMP) during LPS- and simvastatin-induced apoptosis. Furthermore, apoptosis was accompanied by Bcl-2-associated X protein (Bax) translocation to the mitochondria. Our findings suggest that NR4A1 expression and mitochondrial translocation of Bax are related to simvastatin-induced apoptosis in LPS-activated RAW 264.7 macrophages.

A Study on Assessment Items Analysis for Eco-corridors' Area - Using the Analytic Hierarchy Process - (생태통로 우선 설치지역의 평가항목 중요도 분석 - AHP 기법을 적용하여 -)

  • Park, Jihee;Yoo, Heonseok;Park, Miyoung
    • Journal of Environmental Impact Assessment
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    • v.18 no.5
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    • pp.301-312
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    • 2009
  • Recently, habitat fragmentation and shrinkage has occurred because of increased road construction. As a measures mitigating the adverse effect such as eco-island by road construction, Korea has been installed eco-corridors since 1995. Using the Analytic Hierarchy Process (AHP), this study analyzed the importance of assessment items and the criteria to determine which areas require eco-corridors the most. First, related literature reviews, preliminary surveys, and expert interviews were carried out to develop assessment items and criteria for constructing the hierarchy. Second, experts were surveyed in order to determine the relative importance of the assessment items by applying the AHP. As a result, it found that the restoration of the ecological network was the most important assessment item, followed by wild animal resources in the Level 3. In the Level 4, the eighteen items were ranked in the order of their relative weight and it was found that the 'Baekdudaegan Mountain Range (0.189)' was the highest ranked item. Therefore, this approach can be applied to effective selection of the priority areas in planning eco-corridors in the national scale.

A many-objective evolutionary algorithm based on integrated strategy for skin cancer detection

  • Lan, Yang;Xie, Lijie;Cai, Xingjuan;Wang, Lifang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.1
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    • pp.80-96
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    • 2022
  • Nowadays, artificial intelligence promotes the rapid development of skin cancer detection technology, and the federated skin cancer detection model (FSDM) and dual generative adversarial network model (DGANM) solves the fragmentation and privacy of data to a certain extent. To overcome the problem that the many-objective evolutionary algorithm (MaOEA) cannot guarantee the convergence and diversity of the population when solving the above models, a many-objective evolutionary algorithm based on integrated strategy (MaOEA-IS) is proposed. First, the idea of federated learning is introduced into population mutation, the new parents are generated through sub-populations employs different mating selection operators. Then, the distance between each solution to the ideal point (SID) and the Achievement Scalarizing Function (ASF) value of each solution are considered comprehensively for environment selection, meanwhile, the elimination mechanism is used to carry out the select offspring operation. Eventually, the FSDM and DGANM are solved through MaOEA-IS. The experimental results show that the MaOEA-IS has better convergence and diversity, and it has superior performance in solving the FSDM and DGANM. The proposed MaOEA-IS provides more reasonable solutions scheme for many scholars of skin cancer detection and promotes the progress of intelligent medicine.

Ecological Connectivity and Network Analysis of the Urban Center in a Metropolitan City (대도시 도심의 생태적 연결성 및 연결망 분석)

  • Jaegyu Cha
    • Journal of Environmental Impact Assessment
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    • v.32 no.6
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    • pp.503-515
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    • 2023
  • The disconnection and fragmentation of ecological spaces that occur during the development process pose a significant threat to biodiversity. Urban center areas with high development pressure are particularly susceptible to low connectivity due to a scarcity of ecological space. This issue tends to be more pronounced in larger cities.To address this challenge, continuous efforts are needed to assess and improve the current state of ecological space connectivity at the level of individual projects and urban management. However, there is a lack of discussion regarding the analysis and improvement of ecological connectivity in metropolitan cities In line with this objective, this study evaluated the connectivity of ecological spaces in the city centers of Seoul, Busan, Daegu, Incheon, Gwangju, Daejeon, and Ulsan. The evaluation revealed that city centers exhibited lower connectivity of ecological spaces compared to their peripheries or the overall city. In addition, in the ecological network analysis that reflected regional characteristics, such as the species distribution model conducted on Daejeon, 510 optimal paths connecting forests of more than 1ha were derived. This study is significant as an example of deriving an ecological network based on regional characteristics, including quantitative figures necessary for establishing goals to improve urban ecological connectivity and biodiversity. It is anticipated that the results can be utilized to propose directions for enhancing ecological connectivity in environmental impact assessments or urban management and to establish an evaluation framework.

Induction of apoptosis by etoposide treatment in colon cancer cell line SNU C2A (대장암 세포주 SNU C2A에서 etoposide 처리에 의한 apoptosis 유도)

  • Jung, Ji-Yeon;Na, Yun-sook;Jung, Ho-Chul;Oh, Sang-Jin
    • IMMUNE NETWORK
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    • v.1 no.3
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    • pp.221-229
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    • 2001
  • Background: Inactivation of tumor suppressor genes is believed to be important in the development of many human malignancies. Recently, several lines of evidence have indicated that the wild type p53 gene located at 17p13.3, may function as a tumor suppressor gene and that a mutant p53 gene could promote transformation by inactivating normal p53 function in a dominant negative fashion. These broad spectrum of p53 mutation in human cancers provide that mutant p53 and their protein may be potential targets of tumor diagnostic and therapeutic interventions. Method: Colony formation was performed to investigate growth suppressional ability. p53 expression pattern was examined by western blot and p53-mediated transactivation ability was assessed by CAT activity. SNU C2A cells were observed in apoptotic aspects induced by etoposide and $H_2O_2$ treatment, detecting sensitivity on agent, DNA fragmentation through agarose gel, chromatin condensation by fluorescence microscope, and cell cycle distribution by FACS. Result: 1) p53 mutant his179arg ($histidine{\rightarrow}arginine$) detected in SNU C2A cells lost transcriptional activity and growth suppression ability, showing dominant negative effect on its wild type p53. 2) Etoposide-treated SNU C2A cells induced apoptosis, exhibiting dramatic reduction of cell growth, DNA fragmentation, nuclear condensation formation of apoptotic body and increment of sub-G1 cell fraction. 3) Etoposide and $H_2O_2$-treated SNU C2A cells have no high increase of p53 expression and overexpressed p53 protein changed localization, from cytoplasm to nucleus. Also, p53-mediated transcriptional activity was increased by agents-treatment. Conclusion: SNU C2A cells coexpress wild-type and mutant p53 protein induced apoptosis in the condition on DNA damage, through localizational shift from cytoplasm to nucleus of p53 protein rather than the induction of p53 protein. SNU C2A cells derived mutant p53 his179arg abrogated both the growth supression ability and transactivational activity, showing inhibition effect on transcriptional activity of wild type p53, but did not repress the activity of wild type p53 in SNU C2A cells owing to dominant activity of wild type. These cell condition may provide new gene therapeutic implications leading effective antiproliferation of cell when mutant and wild-type p53 protein were co-expressed in cell.

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