• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.404-410
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• 2009

This study was carried out to develop a self-propelled type explosive subsoiler for improving the root zone soil conditions in orchard and other forest fields. Prototype was designed to be able to inject air and other soil improving material such as lime into soil at the same time, and thus improve the air permeability and drainage of orchard soils to promote the root growth of tree for high quality fruit production. Soil penetration device of explosive subsoiler is composed of air hammer, penetration rob and air injection nozzle. To support the soil penetration device of explosive subsoiler to penetrate vertically, modified Scott-Russel mechanism was used. Timing control device for simultaneous injection of soil improving material with air was attached to the out side wall of air cylinder and as the cylinder move, the soil improving material was injected into soil at the same time. Turning radius of prototype was 2.2-2.3 m with good mobility in sloped land. It took approximately 1 minute for lime injection system to reach the optimum pressure of 9.9 kg/$cm^2$, average 10-20 seconds were required to rupture soil with the depth of 50 cm and 2-3 seconds were required for explosion, so all in all about 1 minute and 20 seconds were required for one cycle of explosion. Maximum soil rupture depth and diameter were 50 cm and 3-4 m respectively depending on the soil type and soil moisture content. For final design of explosive subsoiler inclination angle of lime hopper was increased from 60 degree to 70 degree and the shape of hopper was changed from rectangular cone to circular cone to solve the clogging problem of lime at out let. Agitating system operated by compressed air was attached to the metering device of the prototype, thus more than 90 cc of lime was discharged per cycle from metering device without clogging problems.

• The Journal of the Korea Contents Association
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• v.5 no.1
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• pp.89-99
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• 2005

HPI system provides 1-3 Mbps data transmission speed to terminals moving up to 60 km/sec. Since HPI supports rtPS, nrtPS, and BE services requiring different QoS, it needs an efficient scheduling method based on those different QoSs. This paper suggests an uplink scheduling method which gives priority to services in the order of rtPS, nrtPS and BE services but which reserves some bandwidth for the low priority services before it allocates the bandwidth to higher priority services. Simulation results show that it can improve the uplink performance by reserving mean transmission rate to each nrtPS terminal and by reserving bandwidth, which amounts to about 1.5 times the mean transmission rate of the whole BE terminals, to the whole BE terminals.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.13-23
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• 2009

One of the main purpose of multiple-view image processing technology is support realistic 3D image to device user by using multiple viewpoint display devices and compressed data restoration devices. This paper proposes a multiple view image synthesis scheme based on RAM disk which makes possible to browse 3D images generated by applying effective composing method to real time input stereo images. The proposed scheme first converts input images to binary image. We applies edge detection algorithm such as Sobel algorithm and Prewiit algorithm to find edges used to evaluate disparities from images of 4 multi-cameras. In addition, we make use of time interval between hardware trigger and software trigger to solve the synchronization problem which has stated ambiguously in related studies. We use a unique identifier on each snapshot of images for distributed environment. With respect of performance results, the proposed scheme takes 0.67 sec in each binary array. to transfer entire images which contains left and right side with disparity information for high quality 3D image browsing. We conclude that the proposed scheme is suitable for real time 3D applications.

• KIISE Transactions on Computing Practices
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• v.23 no.3
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• pp.171-176
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• 2017

Recently, several information-technology research projects such as those for high-performance computing, the cloud service, and the DevOps methodology have been advanced to develop the efficiency of satellite data-processing systems. In March 2019, the Geostationary Ocean Color Imager II (GOCI-II) will be launched for its predictive capability regarding marine disasters and the management of the fishery environment; moreover, the GOCI-II Ground Segment (G2GS) system for data acquisition/processing/storing/distribution is being designed at the Korea Ocean Satellite Center (KOSC). The G2GS is composed of the following six functional subsystems: data-acquisition subsystem (DAS), data-correction subsystem (DCS), precision-correction subsystem (PCS), ocean data-processing subsystem (ODPS), data-management subsystem (DMS), and operation and quality management subsystem (OQMS). The G2GS will enable the real-time support of the GOCI-II ocean-color data for government-related organizations and public users.

• Journal of KIISE:Databases
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• v.27 no.2
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• pp.209-215
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• 2000

In the on-demand services like AOD(Audio On Demand) over the internet, existing operating systems cannot serve repeatedly requested data efficiently. This paper proposes a web cache architecture. It predicts the songs to be requested in near future, based on the intervals between the requests in the past on the same song and keeps the songs in the web cache. For the replacement strategy of the web cache, LFRR(Least Frequently Requested Recently) is proposed. LFRR replaces the song that has less probability to be requested in near future. The average of the intervals between the requests in the past and the new request is used as the probability of the requests. It is more likely to be requested in near future as the average is less. The web cache decreases the number of disk access extremely, and support to serve more users with restricted resources. From the simulation result based on the data at the AOD site currently operating, it is shown that the high performance enhancement is achieved.

• Journal of KIISE
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• v.43 no.6
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• pp.613-620
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• 2016

This paper presents a MOHA(Many-Task Computing on Hadoop) framework which aims to effectively apply the Many-Task Computing(MTC) technologies originally developed for high-performance processing of many tasks, to the existing Big Data processing platform Hadoop. We present basic concepts, motivation, preliminary results of PoC based on distributed message queue, and future research directions of MOHA. MTC applications may have relatively low I/O requirements per task. However, a very large number of tasks should be efficiently processed with potentially heavy inter-communications based on files. Therefore, MTC applications can show another pattern of data-intensive workloads compared to existing Hadoop applications, typically based on relatively large data block sizes. Through an effective convergence of MTC and Big Data technologies, we can introduce a new MOHA framework which can support the large-scale scientific applications along with the Hadoop ecosystem, which is evolving into a multi-application platform.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.5
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• pp.606-610
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• 2010

In order to provide effective studies in accordance with the shifts in learning paradigms, an LD Publication engine, which is the former engine from the Learning Design (LD) based learning management system, was designed and implemented. The LD Publication engine analyzes the learning contents packages that have been prepared based on the LD and analyzes the constructions and meanings of the information files that describe learning activities in order to model them. The modeled data are fragmentized into effective and accessible forms from in the learning management systems and are then put into the database. LD based learning management systems provide learning effects and learner convenience designed to provide learners with a high performance learning platform. In addition, they will activate the development of content through the reproduction, reuse and sharing of the learning content, which will contribute to the expansion of infrastructures. These systems are also designed to enable linkages among learners' competences, preferences and portfolio, and thus the systems can be easily expanded.

• Asian Journal for Public Opinion Research
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• v.8 no.3
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• pp.265-296
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• 2020

Macao, a special administrative region of China, has been able to maintain the records of zero deaths and keep confirmed cases under 50 since the outbreak of COVID-19 for more than half a year as of July 2020, despite being the world's most densely populated city. The current paper utilizes the dialogic public relations theory to analyze the situation using both literature review on how the various government actions and strategies during the pandemic were corresponding to the theory, and a quantitative random digital dialing (RDD) telephone survey, with a sample of 502 Macao residents aged 18 or above, to study the public reactions towards the government pandemic prevention actions. Survey results show a high level of public satisfaction towards epidemic prevention performance, as well as some forms of collaborative information redissemination behavior in social media platforms. Literature review and analysis from dialogic theory found that spirit of mutual equality, collaboration with local community, immediacy of presence in crisis time, engagements with stakeholders through maximum media channels and networks, supportiveness to public with both useful information and practical social support like subsidy program, as well as commitment to transparent and genuine communication, are all the dialogic communications strategies that describe what the Macao government has done in the crisis of COVID-19. The dialogic strategies that could be learned from the Macao government may be used as a reference for similar urbanized and densely populated cities in other territories.

• Journal of Advanced Navigation Technology
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• v.10 no.1
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• pp.63-69
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• 2006

Recently there are increasing needs for Internet and various kinds of contents. These traffics for various contents need more amount of data to provide high-quality information and require various QoS depending on the characteristics of contents. However, current Internet service supports BE (Best Effort) service only, therefore IntServ (Integrated Service) scheme and DiffServ (Differentiated Service) scheme are represented to support QoS in IP layer. Moreover, while wireless Internet is getting popular, MAC(Medium Access Control) is also becoming important. This is due to the fact that wireless access, resource allocation and packet scheduling, which are done in another layers before, are performed in MAC layer in many new wireless systems. This paper describes new scheme that provides QoS taking into account the traffic characteristics over Mobile IPv6 network based on IEEE 802.11e EDCF and evaluates the performance through computer simulation.

• Journal of KIISE:Databases
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• v.31 no.1
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• pp.1-12
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• 2004

As network systems are developed rapidly and network architectures are more complex than before, it needs to use PBNM(Policy-Based Network Management) in network system. Generally, architecture of the PBNM consists of two hierarchical layers: management layer and enforcement layer. A security policy server in the management layer should be able to generate new policy, delete, update the existing policy and decide the policy when security policy is requested. And the security policy server should be able to analyze and manage the alert messages received from Policy enforcement system in the enforcement layer for the available information. In this paper, we propose an alert analyzer using data mining. First, in the framework of the policy-based network security management, we design and implement an alert analyzes that analyzes alert data stored in DBMS. The alert analyzer is a helpful system to manage the fault users or hosts. Second, we implement a data mining system for analyzing alert data. The implemented mining system can support alert analyzer and the high level analyzer efficiently for the security policy management. Finally, the proposed system is evaluated with performance parameter, and is able to find out new alert sequences and similar alert patterns.