• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.27-36
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• 2018

In this paper, we design and implement a real time IoT messaging system that can collect location information of moving vehicles and pedestrians in real time using MQTT protocol and provides location based information service in administrative area. We implemented MQTT based IoT device for vehicle location information collection and communication and MQTT based smartphone application for pedestrian location information service. IoT clients can send messages to the server in administrative units by using the MQTT Topic which is equal to administrative names. The SLIMS (Seoul Location based IoT Messaging System) implemented in this study is able to analyze the real time traffic volume of pedestrians and vehicles by tracking clients. It also can deliver messages to clients based on coordinate range. SLIMS can be used as a real-time location-based information service for large-scale IoT devices such as real-time flow population and vehicle traffic analysis and location-based message delivery.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.485-487
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• 2017

With the growth of the IoT, security is a growing concern. Things the risk of IoT security has been constantly raised, and there have been many cases of hacking. As a result, there is a growing concern and scale about security, but there is a lack of interest and research on the message protocols between Iot devices. With the development of the IoT, the importance of low-power, lightweight and accurate message delivery will become more important and more advanced message protocols will be needed. In this paper, it is aimed to construct the system for communication between client and server of MQTT and CoAP with Confirmative option, which are most used among IoT message protocols and compare the message reliability of each communication protocol to check efficiency.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.597-601
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• 2013

In this study, we present simple microfluidic approach for the synthesis of monodisperse microcapsules by using droplet-based system. We generate double emulsion through single step in the microfluidic device having single junction while conventional approaches are limited in surface treatment for the generation of double emulsion. First, we have injected disperse fluid containing FC-77 oil and photocurable ethoxylated trimethylolpropane triacrylate (ETPTA) and water containing 3 wt% poly(vinyl alcohol) (PVA) as continuous phase into microfluidic device. Under the condition, we easily generate double emulsion with high monodispersity by using flow focusing. The double emulsion droplets are transformed into microcapsules under the UV irradiation via photopolymerization. In addition, we control thickness of double emulsion's shell by controlling flow rate of ETPTA. We also show that the size of double emulsions can be controlled by manipulation of flow rate of continuous phase. Furthermore, we synthesize microcapsules encapsulating various materials for the application of drug delivery systems.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.21-26
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• 2009

Presently, the demand for IPTV, to satisfy a variety of goals, is exploding. IPTV is coming into the spotlight as a killer application in upcoming IP convergence networks such as triple play which is the delivery of voice, internet, and video service to a subscriber. IPTV utilizes CAS, which controls the subscriber access to content for a profit. Although the current CAS scheme provides access control via subscriber authentication, there is no authentication scheme for the content transmitted from service providers. Thus, there is a vulnerability of security, through which an adversary can forge content between the service provider and subscribers and distribute malicious content to subscribers. In this paper, based on a hash tree scheme, we proposed efficient and strong source authentication protocols which remove the vulnerability of the current IPTV system. We also evaluate our protocol from a view of IPTV requirements.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.78-86
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• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.29-36
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• 2005

As computing environments are more rapidly developed, an adaptive and intelligent services using post PC such as PDA. Laptop, and Tablet PC in case of rounding and examining patients are highly demanded. The objective of this study is to design and implement a context-awareness support system based on voice service for medical environments. To achieve it, we propose a context middleware which plays an important role in recognizing a client with PDA by using a Bluetooth wireless communication technology as well as in executing an appropriate execution module, like delivery for diagnosis information of patients, according to the staff's context acquired from a context server. In addition, the context server functions as a manager that efficiently stores context information such as client's current status, physical environment, and device resources into a database server. Finally, for verifying the usefulness of the proposed system, we develop an application system which provides voice playing services for notification of other physicians through our context middleware.

• Spatial Information Research
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• v.3 no.1
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• pp.1-18
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• 1995

Despite the widespread use of GIS over the past ten years, it has been limited application for regional modeling of pollutant loadings such as sediment, nitrogen, and phosphorus(non-point source pollution), The goals of this study were to: select important processes and parameters of watersheds that contribute to non-point source pollution degradation, develop a ranking model to use the environmental geologic data and verify the model by comparing results with existing water quality data(Chung-ju Lake) for specific watersheds, The GIS database consisted of topography, geology, soils, precipitation, rainfall erosivity, land use, and watershed boundaries. The index(NPSP) for assessing non-point source pollution was comprised in the following three seperate components: soil loss index(SLI) assesses the potential soil erosion and sedim-ent delivery from field to stream; run-off potential ratio(R.P.R) predicts the potential production of surface runoff; chloropgyll-a index ranks the potential manure(animal or human) production within a watershed. The GIS model was a valuable tool to assess the impact of environmental pollation in watersheds.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.4
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• pp.26-33
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• 2012

Please WBAN(Wireless Body Area Networks) is wireless communication of within 3 m radius from inside and outside of the body. WBAN is many uses IEEE 802.15.4 MAC protocol for WBAN MAC protocol requirements. IEEE 802.15.4 MAC protocol applies GTS(Guaranteed Time Slot) allocation scheme for guarantee packet delivery of application which requests QoS(Quality of Service). However, GTS allocation scheme of IEEE 802.15.4 MAC protocol uses FIFS(First In First Service) queueing. So it reduces data transmission reliability and has many problems. Therefore, IEEE 802.15.4 applies not WBAN MAC protocol for emergency data transmission. In this paper, we proposes a priority based MAC protocol for emergency data transmission in wireless body area networks. the proposal MAC protocol sets priority the data. So GTS reqeuest throughput of emergency data increasing and GTS allocation delay of emergency data decreasing.

• Journal of National Security and Military Science
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• s.8
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• pp.271-309
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• 2010

The main theme of this study is about North Korea's contemporary military strategy which remained a blind spot in the 21st century. Indeed, Pyongyang's contemporary military strategy is evolved from the logic of War. On the basis of this logic, this study examined North Korea's contemporary military strategy with three analytical frameworks. The first is the discovery of Clausewitz's dictums and application of the Trinitarian analysis on the Korean cases. During the course of applying Clausewitzian main dictum--War as continuation of politics, the methodological analysis on war played a important role generalizing the pattern and matrix of North Korea's strategic thinking and military strategy. In particular, Clausewitz's Trinitarian framework on war -Government (reason), Army (chance), People (passion)- was a universal framework to scrutinize the North Korean missile and nuclear strategy. The second is about the matrix of North Korea's military strategy, The study suggested the genealogical feature of Pyongyang's military strategy. In principle, the dictum of 'Military-First Politics' 1S the combination of the political philosophy, Chuch'e (self-reliance) of Kim Il Sung and Kin Jong Il reflected in the military readiness. As a result this analysis was able to equate Clausewitz's dictums to explain Pyongyang's idea of the nature of war in that North Korea's military strategy is the central instrument of delivery to achieve political objectives. The third is about the theoretical encounter of 'Clausewitz's Wonderful Trinity' and 'Remarkable Trinity on North Korea's contemporary strategy'. On the basis, three elements are connected to one of three groups in society; the people, the military, and the government. In order to apply the Clausewitz's Trinitarian analysis into Kim Jong Il's 'Military-First' strategy, two case studies (Missile and Nuclear strategy) were examined. The finding of this study is that Clausewitzian dictum in the 19th century is still valid in the 21st century as it provided plausible theoretical framework to explain the North Korean contemporary military strategy with a reminder that the nature and logic of war are fixed in the socially constructed state.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.43-50
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• 2007

Delay in the process of Information Extraction, IE, is largely due to inability to correctly recognize the user's information requirement of particular search factors. Especially if the wrapper rules are used in a search engine, the search generally fails to classify internet documents properly and efficiently since the application of the same wrapper rules lacks extensibility throughout various types of existing internet document. In case of buying or selling a ship, if the price range, type. place of delivery, inspection site and other information relevant to the sales would be available through the internet for proper retrieval the sales could more readily succeed by using Ontology relating to sales or purchase information and by selectively searching for the desired information through the content based retrieval system. This system proposes to improve various wrapper systems existing throughout different internet sites and to eliminate unnecessary information tagged on the existing internet documents in order to create a more advanced information retrieval system.