• Journal of KIISE:Databases
• /
• v.31 no.4
• /
• pp.422-431
• /
• 2004

In recent years, different models in data delivery have been explored in mobile computing systems. Particularly, there were a lot of research efforts in the periodic push model where the server repetitively disseminates information without explicit request. However, average waiting time per data operation highly depends on the length of a broadcast cycle and different access pattern among clients may deteriorate the response time considerably. In this case, clients are preferably willing to send a data request to the server explicitly through backchannel in order to obtain optimal response time. We call the broadcast model supporting backchannel as hybrid broadcast. In this paper, we devise a new transaction processing algorithm(O-PreH) in hybrid broadcast environments. The data objects which the server maintains are divided into Push_Data for periodic broadcasting and Pull_Data for on-demand processing. Clients tune in broadcast channel or demand the data of interests according to the data type. Periodic invalidation reports from the server support maintaining transactional consistency. If one or more conflicts are found, conflict orders are determined not to violate the consistency(pre-reordering) and then the remaining operations have to be executed pessimistically. Through extensive simulations, we demonstrate the improved throughput of the proposed algorithm.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.3
• /
• pp.209-218
• /
• 2011

In low voltage high current applications such as fuel cells the current-fed DC-DC converter which has small ripple current and turn ratio is more efficient. In the applications larger than 5kW the conventional single-phase current-fed converter based on full-bridge, half-bridge or push-pull topologies has high current burden of devices such as switches, and the selection and optimized design of the devices are not easy. In this paper a three-phase active-clamped current-fed push-pull DC-DC converter suitable for high power high step-up applications is proposed. The proposed converter has reduced current burden and is suitable for wide input voltage applications due to the use of whole duty cycle range. Design methods of main components including three-phase high frequency transformers are provided, and the validity and performance of the proposed converter are proved from a 5kW prototype.

• Journal of KIISE:Computing Practices and Letters
• /
• v.6 no.1
• /
• pp.68-81
• /
• 2000

CORBA Trader Service is to locate appropriate objects that provide the desired functionality at runtime. To provide this service, the Trader Service federates a local trader and remote traders by considering the Traders or Link policies, and it returns the service offers that are requested by the importer. This traditional way of trading reveals a performance problem due to the low response time. The response time largely depends on the amounts of service offers of the Importer's request and the frequency of federations with the other trader. The performance is a key factor for evaluating the Trader Service performance.In order to overcome the low response time and to provide the high-quality services, we propose new policies of Import and Trader, and present a PUTS(Push Trader Service) model which implements this new advanced trader service. We present the design and implementation of the PUTS's major modules, also make a comparison between PUTS system and traditional trader system in terms of performance and functionality through case studies.

• Journal of KIISE:Computing Practices and Letters
• /
• v.10 no.4
• /
• pp.337-350
• /
• 2004

Because of a security problem and not enough IPv4 address space, the home network has been made up of private network, and it has been separated from Internet. This fact prevents people in Internet from controlling and monitoring home appliances. So, this paper designs and Implements the UPnP Proxy System which offers functions for users to control and monitor home appliances. When users are in the outside of the home network, they do not know which devices were connected in the home network because the advertisement messages of UPnP devices would not be delivered to the outside of the home network. Also, users cannot access devices directly, and their control messages are not delivered into the home network. So, this paper designs and implements the UPnP Proxy System to solve these problems. The merit of the system is that users can control and monitor home appliances in realtime using presentation web documents with the HTTP push technology.

• Journal of Navigation and Port Research
• /
• v.32 no.6
• /
• pp.473-479
• /
• 2008

Recently the trade patterns of the entire economy are rapidly changing on development of IT. The field of port logistics is enforcing a competitiveness through preliminary offer of information and a batch process for improving the structure of logistics management which is apparently high cost and the low efficiency since 1990. But a previous EDI is insufficient in process ability. Bemuse it costs for the purchasing and maintenance of the expensive communication devices which is operated on the VAN environment. A web based EDI operating on an open network environment is needed to improve these problems and to handle transaction efficiently among many and unauthorized personals. Therefore, this study is willing to present a new web based model of the pull process which extracts the data when the receiver is needed to improve the push process which is transmitting data unilaterally.

• Cross-Cultural Studies
• /
• v.51
• /
• pp.45-71
• /
• 2018

This essay explores Louise Erdrich's politically resistant voice which interrogates and disrupts the long-lasting, pernicious misbelief about Native Americans as 'vanishing people'. This essay chiefly focuses on the two female characters-Lulu Nanapush and Marie Lazarre Kashpaw-in the author's widely acclaimed novel Love Medicine (1993). First, illustrating the Chippewas' multifaceted resistances against white Americans' colonialist dominance disclosed in their enforcement of governmental policy, law, religion, and culture, this essay investigates how Erdrich does not stop telling her story that the idea of 'vanishing people'-another version of 'Manifest Destiny'-is unfounded. Second, by referring to Freud's and Marcuse's speculation on 'Eros'-the great unifying energy that preserves all life-as an alternative to the predicament caused by an oppressive civilization, this essay illuminates Erdrich's vision of sustaining and regenerating the Chippewas' tribal life and heritage that center on the embracing power of love reified in Lulu and Marie. Their undying energy consolidating their communal love and ties, despite the destructive, oppressive colonialist milieu inflicted on the Chippewa Indian reservation, sheds light on the author's politics of 'Eros' predicated tightly upon her historical consciousness.

• Cross-Cultural Studies
• /
• v.45
• /
• pp.167-194
• /
• 2016

V.V. Rozanov, a well-known writer and thinker, has wrote many critical essays about Russian literature and writers. The most famous literary criticism written by him is an essay about F. Dostoevsky - Legend of the Grand Inquisitor (1894), which has been highly appraised by N. Berdyaev. If Dostoevsky was the best and the most admirable writer by Rozanov, Gogol was one of the most condemned one by him. This paper, first of all, aims to analyze Rozanov's literary essays about Gogol. At this time, our subjects of analysis included writer's critical essays about Pushkin and Dostoevsky because Rozanov tried to investigate the nature of a creation of Gogol through comparative studies. Based on these analyses, we attempted to deduce an overall view of Rozanov about Russian literature. We also examined the influence of Rozanov on the later criticism.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.11 no.6
• /
• pp.778-783
• /
• 2018

With the rapid advancement of information and communication technology and industrial technologies, a hyper-connected society is being realized to connect human beings, all programs and things via the Internet. IoT (Internet of Thing), which connects a thing and another thing, and things and human beings, gathers information to realize the hyper-connected society. MQTT (Message Queuing Telemetry Transport) is a push-technology-based light message transmission protocol that was developed to be optimized to the limited communication environment such as IoT. In pursuing the hyper-connected society, IoT's sensor environment information is now being used as a wide range of information on people's diseases and health management. Thus, security problems of such MQTT include not only the leak of environmental information but also the personal information infringement. To resolve such MQTT security problems, we have designed a new security MQTT communication by applying the initial-value sensitivity and pseudorandomness of the chaotic system to the integrity and confidentiality. The encryption method using our proposed chaotic system offers a simple structure and a small amount of calculation, and it is deemed to be suitable to the limited communication environment such as IoT.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.8
• /
• pp.1248-1254
• /
• 2022

Efforts are being made to prevent traffic accidents in the school zone in advance. However, traffic accidents in school zones continue to occur. If the driver can know the situation information in the child protection area in advance, accidents can be reduced. In this paper, we design a camera that eliminates blind spots in school zones and a number recognition camera system that can collect pre-traffic information. It is designed by improving the LIDAR system that recognizes vehicle speed and pedestrians. It collects and processes pedestrian and vehicle image information recognized by cameras and LIDAR, and applies artificial intelligence time series analysis and artificial intelligence algorithms. The artificial intelligence traffic accident prevention system learned by deep learning proposed in this paper provides a forced push service that delivers school zone information to the driver to the mobile device in the vehicle before entering the school zone. In addition, school zone traffic information is provided as an alarm on the LED signboard.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.2
• /
• pp.125-130
• /
• 2021

Implementation of livestock smart-farm can be done more effectively with IoT technology developing. An build of useful stock management system can be possibile if push messages of these judgement are notified on smart-phone after cattle's illness and estrus are judged using IoT technology. These judgement method of cattle's illness and estrus can be done with gathering living stock data using temperature sensor and 3 axis acceleration sensor and sending these data using IoT and internet network into server, and studying AI machine learning using these data. In this paper, to build this cattle management system based on IoT, effective system of the whole architecture is showed. Also an effective analysis and design method to develop this system software will be presented by showing user requirement analysis using object-oriented method, flowchart and screen design.