• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.1051-1053
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• 2015

Twitter is using Tweets to post 140 characters at a time to interact with different people around the world. In addition, Twitter will also provide speed, such as instant messaging by providing the follow feature. This was used for increasing the number of users because of the tweeter, a portion of the life was due to the popularity of smart phones. However, because of the large amount of data of the tweeter has a disadvantage similar to the user information or user information is not recommended. In this paper, in order to compensate for this problem to establish a ranking filter the similarity information based on a user's system, we propose that the user or the like similar to the user information. The system proposed in this paper consists of the collected data and modules to collect data using a user account in the filtering and the like to the tweeter module. These modules use the Open API and Mahout designed and implemented.

• Journal of Digital Contents Society
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• 제18권5호
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• pp.895-904
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• 2017

In this paper, we propose an IoT based smart outlet system for one-person household with electric safety, electric energy consumption management and transmission of messages to the reserved contacts by connecting the emergency network. The proposed smart outlet system is implemented by parsing packet data and protocol between server, module, application and WiFi AP receiver. The WiFi AP built for communication can be used not only for the outlet but also for the gas barrier, the door lock and the like. In addition, the proposed method can provide the remote monitoring function by receiving the amount of power of the receptacle received through the AC current sensor (SCT-013) in real time. The smart outlet system is expected to be capable of automatically shutting off the power in case of emergency through automatic power use analysis in addition to the standby power cutoff function.

• Journal of the Korea Society of Computer and Information
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• 제15권6호
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• pp.1-9
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• 2010

This paper proposes a test method for compliance of SMS encoder and decoder modules with 3GPP (3rd Generation Partnership Project) specification on SMS PDU (Protocol Data Unit). The existing tools have focused on providing an SMS gateway and on helping to view and edit a single SMS PDU, which rarely help to resolve the compliance test problem. The proposed compliance test method is based on an automatic generation of SMS PDUs fully compliant with the 3GPP specification by using QuickCheck library written in Haskell. By applying the proposed method to a C-based SMS encoder and decoder in Linux Mobile platform, we have found out several critical bugs such as wrong interpretation of time stamps in BCD format. The automatic SMS PDU generator is reusable in that it only depends on the 3GPP SMS specification. The QuickCheck library is also applicable for testing other network protocol data encoders and decoders, as used in this paper.

• Journal of the Institute of Electronics Engineers of Korea SC
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• 제46권6호
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• pp.73-79
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• 2009

For the shake of control for movement object, control theory like neural network, nonlinear model predictive control(NMPC) is realized on digital high speed computer. Predictor of flight control system(FCS) based nonlinear model predictive control has to be satisfied with response for hard real-time to perform applications on each module in the FCS. Simultaneously, It gives a serious consideration accuracy to give full play to FCS's performance. Error of mathematical aspect affects realization of whole algorithm. But factors of bring mathematical error is not considered to calculate final accuracy on parameter of predictor. In this paper, Predictor was made using load control model on the digital computer for design FCS at hard real-time and is shown response time on realization algorithm. And is shown realization algorithm of high effective predictor over the accuracy. The predictor was realized on the load control model using Euler method, Heun method, Runge-Kutta and Taylor method.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제16권6호
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• pp.208-218
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• 2017

This study aims to develop the Vehicle Local Dynamic Map (V-LDM) and demonstrate its performance for providing dynamic map data efficiently to the vehicle control module. Firstly, the concept of the in-vehicle LDM has been established and then the system has been carefully designed according to the international standards. The high-precision digital map embedded in LDM has been designed to incorporate the lane-level information of road network, and the Dynamic Map protocol (DM protocol) which is a message protocol including the road data with dynamic traffic event data has been defined. The performance test of the proposed system has been conducted in the uninterrupted road section of Kyungbu expressway, showing that both of the data size and the elapsed time to finish the process are almost linearly proportional to the length of target road. Finally, it is recommended that the length of target road for DM protocol be less than 250m.

• Advances in Energy Research
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• 제1권2호
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• pp.97-106
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• 2013

This study designs and tests a photovoltaic system with distributed maximum power point tracking (DMPPT) methodology using a field programmable gate array (FPGA) controller. Each solar panel in the distributed PV system is equipped with a newly designed DC/DC converter and the panel's voltage output is regulated by a FPGA controller using PI control. Power from each solar panel on the system is optimized by another controller where the quadratic maximization MPPT algorithm is used to ensure the panel's output power is always maximized. Experiments are carried out at atmospheric insolation with partial shading conditions using 4 amorphous silicon thin film solar panels of 2 different grades fabricated by Chi-Mei Energy. It is found that distributed MPPT requires only 100ms to find the maximum power point of the system. Compared with the traditional centralized PV (CPV) system, the distributed PV (DPV) system harvests more than 4% of solar energy in atmospheric weather condition, and 22% in average under 19% partial shading of one solar panel in the system. Test results for a 1.84 kW rated system composed by 8 poly-Si PV panels using another DC/DC converter design also confirm that the proposed system can be easily implemented into a larger PV power system. Additionally, the use of NI sbRIO-9642 FPGA-based controller is capable of controlling over 16 sets of PV modules, and a number of controllers can cooperate via the network if needed.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제38B권9호
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• pp.707-714
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• 2013

IoT, which can be regarded as an enhanced version of M2M communication technology, was proposed to realize intelligent thing to thing communications by utilizing Internet connectivity. Things in IoT are generally heterogeneous and resource constrained. Also such things are connected with each other over LLN(low power and lossy Network). Confidentiality, mutual authentication and message origin authentication are required to make a secure service in IoT. Security protocols used in traditional IP Networks cannot be directly adopted to resource constrained devices in IoT. Under the respect, a IETF standard group proposes to use lightweight version of DTLS protocol for supporting security services in IoT environments. However, the protocol can not cover up all of very constrained devices. To solve the problem, we propose a scheme which tends to support mutual authentication and session key agreement between devices that contain only a single crypto primitive module such as hash function or cipher function because of resource constrained property. The proposed scheme enhances performance by pre-computing a session key and is able to defend various attacks.

• Journal of Information Processing Systems
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• 제10권1호
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• pp.103-118
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• 2014

Over the last couple of years, traditional VANET (Vehicular Ad Hoc NETwork) evolved into VANET-based clouds. From the VANET standpoint, applications became richer by virtue of the boom in automotive telematics and infotainment technologies. Nevertheless, the research community and industries are concerned about the under-utilization of rich computation, communication, and storage resources in middle and high-end vehicles. This phenomenon became the driving force for the birth of VANET-based clouds. In this paper, we envision a novel application layer of VANET-based clouds based on the cooperation of the moving cars on the road, called CaaS (Cooperation as a Service). CaaS is divided into TIaaS (Traffic Information as a Service), WaaS (Warning as a Service), and IfaaS (Infotainment as a Service). Note, however, that this work focuses only on TIaaS and WaaS. TIaaS provides vehicular nodes, more precisely subscribers, with the fine-grained traffic information constructed by CDM (Cloud Decision Module) as a result of the cooperation of the vehicles on the roads in the form of mobility vectors. On the other hand, WaaS provides subscribers with potential warning messages in case of hazard situations on the road. Communication between the cloud infrastructure and the vehicles is done through GTs (Gateway Terminals), whereas GTs are physically realized through RSUs (Road-Side Units) and vehicles with 4G Internet access. These GTs forward the coarse-grained cooperation from vehicles to cloud and fine-grained traffic information and warnings from cloud to vehicles (subscribers) in a secure, privacy-aware fashion. In our proposed scheme, privacy is conditionally preserved wherein the location and the identity of the cooperators are preserved by leveraging the modified location-based encryption and, in case of any dispute, the node is subject to revocation. To the best of our knowledge, our proposed scheme is the first effort to offshore the extended traffic view construction function and warning messages dissemination function to the cloud.

• Journal of Microbiology and Biotechnology
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• 제30권9호
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• pp.1355-1366
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• 2020

Sediment bacterial communities are critical to the biogeochemical cycle in river ecosystems, but our understanding of the relationship between sediment bacterial communities and their specific input streams in rivers remains insufficient. In this study, we analyzed the sediment bacterial community structure in a local river receiving discharge of urban domestic sewage by applying Illumina MiSeq high-throughput sequencing. The results showed that the bacterial communities of sediments samples of different pollution types had similar dominant phyla, mainly Proteobacteria, Actinobacteria, Chloroflexi and Firmicutes, but their relative abundances were different. Moreover, there were great differences at the genus level. For example, the genus Bacillus showed statistically significant differences in the hotel site. The clustering of bacterial communities at various sites and the dominant families (i.e., Nocardioidaceae, and Sphingomonadaceae) observed in the residential quarter differed from other sites. This result suggested that environmentally induced species sorting greatly influenced the sediment bacterial community composition. The bacterial co-occurrence patterns showed that the river bacteria had a nonrandom modular structure. Microbial taxonomy from the same module had strong ecological links (such as the nitrogenium cycle and degradation of organic pollutants). Additionally, PICRUSt metabolic inference analysis showed the most important function of river bacterial communities under the influence of different types of domestic sewage was metabolism (e.g., genes related to xenobiotic degradation predominated in residential quarter samples). In general, our results emphasize that the adaptive changes and interactions in the bacterial community structure of river sediment represent responses to different exogenous pollution sources.

• Economic and Environmental Geology
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• 제43권6호
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• pp.649-659
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• 2010

In this study, a tunnel information database system was developed to optimize the process of assessing and analyzing geological information from the life cycle of tunnel construction. All data from every stage in tunnel construction can be put into the system and be utilized for the decision making. In the system, tunnel face mapping information can be managed by digital format which can be easily transformed into 3D visualization module and thus help analyzing geological discontinuities. The system was applied to waterway and road tunnel in domestic area to verify its effectiveness.