• Spatial Information Research
• /
• v.20 no.2
• /
• pp.45-57
• /
• 2012

Recently, local governments in Korea are promoting the rapid development of marine for delineating jurisdictional sea area. The importance of a maritime boundary has being emphasized, as jurisdictional sea area disputes among local governments have been increasing. The absence of the delineating standard of maritime boundary has become a source of contention between neighborhood local governments. So the delineating standard of maritime boundary in Korea will be required. The purpose of this study is to derive an improvement plan for the scientific delimitation standard of maritime boundary by analyzing "A hydrographic survey guideline for confirmation of maritime boundary". The results of this study are as follows. Firstly, we defined the concept of the delimitation standard of maritime boundary. Secondly, we set the boundary, factors and processes of the delineating standard of maritime boundary through classifying them in detail. Lastly, we suggested the makeup of a conflict adjustment committee for preventing jurisdictional sea area disputes among local governments.

• Journal of Korea Multimedia Society
• /
• v.19 no.10
• /
• pp.1808-1815
• /
• 2016

TPSN(Timing-sync Protocol for Sensor Networks), the representative of time synchronization protocol, has been already developed to provide time synchronization among nodes in wireless sensor networks. Even though the TPSN's method has been referenced by so many other time synchronization schemes for resource-constrained networks like wireless sensor networks or low power personal area networks, it has some inefficiency in terms of power consumption and network-wide synchronization time (or called convergence time). The main reason is that each node in TPSN needs waiting delay to solve the collision problem due to simultaneous transmission among competing nodes, which causes more power consumption and longer network convergence time for a network-wide synchronization. In this paper an improved scheme is proposed by changing message exchange method among nodes. The proposed scheme not only shortens network-wide synchronization time, but also reduce collision traffic which lead to needless power consumption. The proposed scheme's performance has been evaluated and compared with an original scheme by simulation. The results are shown to be better than the original algorithm used in TPSN.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2005.11a
• /
• pp.121-124
• /
• 2005

The High Rate Wireless Personal Area Networks (WPAN) is mainly targeted to consumer electronics and portable communication devices which need high rates and QoS. To achieve these goals, the WPAN provides data rates up to 1Gbps and adopts a Time Division Multiple Access (TDMA) MAC protocol. Since IEEE 802.15.3 MAC is based on TDMA scheme, it has good performance in dealing with real traffics. But it does not give better results for dynamic traffic. For dynamic traffic, IEEE 802.15.3 MAC needs a kind of request and response policy that brings about the degradation of performance in order to adapt to network changes. To overcome this problem and enhance the data throughput, this paper proposes a superframe structure which uses the Enhanced Contention Access Period (ECAP) to transmit data during sleep-CTA in PM mode.

• Journal of the Korean Data and Information Science Society
• /
• v.21 no.4
• /
• pp.783-793
• /
• 2010

Several multi-hop applications developed for vehicular ad hoc networks use broadcast as a means to either discover nearby neighbors or propagate useful traffic information to other vehicles located within a certain geographical area. However, the conventional broadcast mechanism may lead to the so-called broadcast storm problem, a scenario in which there is a high level of contention and collisions at the link layer due to an excessive number of broadcast packets. We present a fuzzy alert message dissemination algorithm to improve performance for road safety alert application in Vehicular Ad-hoc Network (VANET). In the proposed algorithm, when a vehicle receives an alert message for the first time, the vehicle rebroadcasts the alert message according to the fuzzy control rules for rebroadcast degree, where the rebroadcast degree depends on the current traffic density of the road and the distance between source vehicle and destination vehicle. Also, the proposed algorithm is the hybrid algorithm that uses broadcast protocol together with token protocol according to traffic density. The performance of the proposed algorithm is evaluated through simulation and compared with that of other alert message dissemination algorithms.

• Journal of the Korea Society for Simulation
• /
• v.17 no.4
• /
• pp.21-27
• /
• 2008

In this paper, we design and implement the upstream packet bandwidth allocation algorithm on OPNET-based DOCSIS 3.0 simulator including channel-bonding CM (Cable Modem)s. Previous DOCSIS CM could not support channel bonding, it has problem in upstream bandwidth allocation and determine the contention area. The proposed upstream bandwidth allocation algorithm has been improved the queuing time and success rate. For the simulation, we design the MAC frame structure with channel bonding supported CM and not. And then, this paper design and implement the CMTS node model, CM node model, CMTS process model, and CM process model.

• Journal of Plant Biology
• /
• v.14 no.3
• /
• pp.1-20
• /
• 1971

Ecological factors limiting Stipa pulchra have been determined in experimental gardens and at several sites in the hills south and east of Monterey, California. The Stipa pulchrafacies of Valley Grassland communities were found to be dominated by that species, though a total of 36 grasses and forbs were collected and identified. Basal area was not large, but aerial cover by Stipa alone averaged over 50 per cent. Across an ecotone between a Stipa association and the California Annual Type a sudden and dramatic change was recorded. Soil measurements there, and in other nearby areas, showed a much higher clay content with more available water and elemental phosphorus at the Stipa sites. Germination of Stipa seeds was high under all laboratory and field conditions, though growth of seeldings was highly variable. Seedlings grown in Stipa woil with an abundance of water were vigorous and reached anthesis the first year. In other soils they grew less, and when grown in competition with Avena fatua they scarcely grew at all. These findings indicate that when established on desirable soils, Stipa competes well and apparently precludes the dominance of Avena fatua and other large annual grasses. On the other hand, because of a lack of vigor in its seedlings, Stipa cannot reinvade the rich more friable soils on which it was once found, and on which it was shown to grow satisfactorily. This supports the contention that Sipa pulchra was the dominant grass through much of the Valley Grassland and Foothill Woodland, but also indicates that well-drained soils and those poor in mineral nutrients probalby never supported such associations.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.7B
• /
• pp.827-833
• /
• 2011

Directional MAC protocols have drawn great attentions recently in super high speed wireless local/personal area networks due to their higher antenna gain, better spatial reuse, longer transmission range, and lower interference. Despite of these merits, directional MAC protocols suffer from deafness problem. The deafness problem occurs if a node does not answer an RTS frame addressed to it. To overcome this problem, directional MAC protocols have aimed at avoiding the deafness problem using multiple control frames or advance notice techniques or distinguishing deafness from collision. In this paper, we analyze the performance of these schemes in deafness environments with some scenarios. Through performance analysis, we compare the performance of these schemes through evaluating actual network throughput.

• Journal of Contemporary Eastern Asia
• /
• v.18 no.1
• /
• pp.1-6
• /
• 2019

During the Obama administration, America made a shift in its foreign policies to re-focus on Asia. The strategy, known as 'Pivot to Asia', was used to contain a rising China. In this editorial note, I appropriate the geopolitical term to call for a scholarly refocus on Asia (and the broader Asia Pacific region). JCEA started as an area journal. While it has become more technology-focused and less geographically-bounded in its coverage of topics, the journal recognizes the centrality of the region's political economy and technological forces in setting (and upsetting) global norms and rules. The Asia Pacific contains the world's freest economies as well as the most oppressive regimes. It breeds both technology giants and laggards. As new geopolitical tensions loom, it is where the digital iron curtain is drawn, and where the vice and virtue of innovations debated. Social scientists in the English world, who lend extensively on European and American cases, can benefit from studying the Asia Pacific by testing whether and how local experience conforms to or confronts with universal theories. Very likely, western-centric norms and models become morphed and entangled in the grounded local particularity, reflecting many shades of this diverse place. In my arguments below, I highlight the Asia Pacific as a site of contradiction, as well as a site of contention and negotiation. My emphasis is that regional particularity holds the key to answer concurrent debates in the West concerning governance and accountability in the digital age.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.5
• /
• pp.239-247
• /
• 2013

In network based on multi-interface, there are needed channel assignment strategy that reduce interference and improve bandwidth efficiency by assigning each interface to available channels in order to utilize effectively multiple wireless interfaces on each node. MCS protocol had been proposed, which improve capacity and throughput of network by using hybrid assignment. MCS uses as the criterion to assign channel the number of node that use the same channel in contention area. but there have an problem that this information exactly does not reflect actually offered channel load. in this paper, we proposes CAMCS protocol to assign channel by that the channel busy degree to indicate the occupancy rate of channel by nodes as well as the number of nodes that use the same channel in inference area is used as criterion for estimation channel load, and conform performance improvement effect by simulation.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.12
• /
• pp.121-129
• /
• 2012

In this paper, we proposed WBAN system model to management an application that requires low rate data transfer in IEEE 802.15.4. We have to use different wireless sensor network technology to transfer different date rate and emergency message in medical application service. A suitable system model for WBAN and a WBAN MAC protocol in order to solve these existing system problems are proposed. Firstly, the priority queuing was applied to contention access period, and the system model which could guarantee transmission of a MAC command frame was proposed. Secondly, the MAC frame was newly defined to use the system model which was proposed above. Thirdly, WBAN CSMA/CA back-off algorithm based on data transmission rate was proposed to enhance data throughput and transmission probability of the data frame which does not have priority in the proposed WBAN system. The proposed algorithm is designed to be variable CSMA/CA algorithm parameter, depending on data rate. For the evaluation of WBAN CSMA/CA algorithm, we used Castalia. As a result of the simulation, it is found that the proposed system model can not only relieve loads of data processing, but also probability of collision was decreased.