• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2276-2283
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• 2010

This study investigated the needs of u-City related civil servants upon guideline which is constituted for efficient promotion of the u-City IT infra construction. It utilized explanatory design in mixed method as a research design. In the research result, respondents needed as follows : 1)law and institutions involved in construction processes, 2)information about engineering techniques with general terms in u-City constructions, 3)reference service models. It proposed implications of constructing the new guideline based upon research results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.839-842
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• 2011

Lately Various researches on energy harvesting techniques for wireless sensor networks have been performed to overcome the power limitation of sensor nodes. In wireless sensor networks with harvesting techniques, sensor nodes exploit environmental energy, such as solar or wind energy, as the power sources of the nodes. Existing energy constrained environment routing protocols may not be suitable for energy harvesting based wireless sensor networks because they do not consider the accumulated energy from harvesting devices. In addition, the paths which aren't dispersed shorten the network lifetime. Therefore, in this paper, the algorithm that the path between each node is dispersed is proposed. In case of using the algorithm to be proposed through the simulator it showed that path of the node is variously reflected.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4844-4864
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• 2017

Interference-aware routing protocol design for underwater wireless sensor networks (UWSNs) is one of the key strategies in reducing packet loss in the highly hostile underwater environment. The reduced interference causes efficient utilization of the limited battery power of the sensor nodes that, in consequence, prolongs the entire network lifetime. In this paper, we propose an energy-efficient interference-aware routing (EEIAR) protocol for UWSNs. A sender node selects the best relay node in its neighborhood with the lowest depth and the least number of neighbors. Combination of the two routing metrics ensures that data packets are forwarded along the least interference paths to reach the final destination. The proposed work is unique in that it does not require the full dimensional localization information of sensor nodes and the network total depth is segmented to identify source, relay and neighbor nodes. Simulation results reveal better performance of the scheme than the counterparts DBR and EEDBR techniques in terms of energy efficiency, packet delivery ratio and end-to-end delay.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.177-186
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• 2000

An improved multi-level（IML) optimization algorithm using automatic differentiation (AD) for multi-objective optimum design of framed structures is proposed in this paper. In order to optimize the steel frames under seismic load, two main objective functions need to be considered for minimizing the structural weight and maximizing the strain energy. For the efficiency of the proposed algorithm, multi-level optimization techniques using decomposition method that separately utilizes both system-level and element-level optimizations and an artificial constraint deletion technique are incorporated in the algorithm. And also to save the numerical efforts, an efficient reanalysis technique through approximated structural responses such as moments, frequencies, and strain energy with respect to intermediate variables is proposed in the paper. Sensitivity analysis of dynamic structural response is executed by AD that is a powerful technique for computing complex or implicit derivatives accurately and efficiently with minimal human effort. The efficiency and robustness of the IML algorithm, compared with a plain multi-level (PML) algorithm, is successfully demonstrated in the numerical examples.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.333-342
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• 1999

An improved optimization algorithm for multi-objective and multi-level (MO/ML) optimum design of steel frames is proposed in this paper. In order to optimize the steel frames under seismic load, two main objective functions need to be considered for minimizing the structural weight and maximizing the strain energy. For the efficiency of the proposed method, well known multi-level optimization techniques using decomposition method that separately utilizes both system-level and element-level optimizations and an artificial constraint deletion technique are incorporated in the algorithm. And also dynamic analysis is executed to evaluate the implicit function of structural strain energy at each iteration step. To save the numerical efforts, an efficient reanalysis technique through sensitivity analysis of dynamic properties is unposed in the paper. The efficiency and robustness of the improved MOML algorithm, compared with a plain MOML algorithm, is successfully demonstrated in the numerical examples.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.126-132
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• 2005

UV disinfection system allows the disinfection of municipal and industrial water and wastewater without the use of expensive chlorination and dechlorination techniques, labor intensive equipments In traditional ultraviolet systems the UV lamps are seperated from water by quartz sleeves. quartz is one of. the few materials that is virtually transparent to UV light, the UV lamp is placed inside the Quartz sleeve. UV light from the lamp is passed through the quartz and into the water, thereby providing disinfection. In fluoropolymer tube-used non-contact UV systems, the water flows through fluoropolymer plastic tubes. banks of UV lamps surround these tubes such that each tube gets exposed to ultra violet light from all sides. in non-contact design the lamps operates at almost constant temperature. this design is extremly efficient in the utilization of UV energy and superior to conventional contact- systems.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.22-30
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• 2009

Due to high levels of integration and complexity, the Network-on-Chip (NoC) approach has emerged as a new design paradigm to overcome on-chip communication issues and data bandwidth limits in conventional SoC(System-on-Chip) design. In particular, exponentially growing of energy consumption caused by high frequency, synchronization and distributing a single global clock signal throughout the chip have become major design bottlenecks. To deal with these issues, a globally asynchronous, locally synchronous (GALS) design combined with low power techniques is considered. Such a design style fits nicely with the concept of voltage-frequency-islands (VFI) which has been recently introduced for achieving fine-grain system-level power management. In this paper, we propose an efficient design methodology that minimizes energy consumption by VFI partitioning on an NoC architecture as well as assigning supply and threshold voltage levels to each VFI. The proposed algorithm which find VFI and appropriate core (or processing element) supply voltage consists of traffic-aware core graph partitioning, communication contention delay-aware tile mapping, power variation-aware core dynamic voltage scaling (DVS), power efficient VFI merging and voltage update on the VFIs Simulation results show that average 10.3% improvement in energy consumption compared to other existing works.

• Smart Media Journal
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• v.6 no.4
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• pp.24-31
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• 2017

In wireless sensor networks, sensor nodes are deployed in a remote, harsh environment. When the power of the sensor node is consumed in such a network, the sensor nodes become useless together with the deterioration of the quality and performance of the sensor network which may save human life. Although many clustering protocols have been proposed to improve the energy consumption and extend the life of the sensor network, most of the previous studies have shown that the overhead of the cluster head is quite large. It is important to design a routing protocol that minimizes the energy consumption of each node and maximizes the network lifetime because of the power limitations of the sensor nodes and the overhead of the cluster heads. Therefore, in this paper, we propose an efficient clustering scheme that reduces the burden of cluster heads, minimizes energy consumption, and uses algorithms that maximize network lifetime. Simulation results show that the proposed clustering scheme improves the energy balance and prolongs the network life when compared with similar techniques.

• Journal of Digital Contents Society
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• v.9 no.1
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• pp.1-6
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• 2008

In traditional wireless communication systems the main power consumption is due to the actual transmissions power. Therefore, energy-constrained wireless networks have gained considerable research attention in recent years. Multiple-input-multiple-output (MIMO) structure, or multiple antenna communication is one of the techniques that has gain considerable importance in wireless systems and networks. In this paper, BER and throughput performance of MISO system with Go-back-N ARQ(Automatic Repeat Request) technique in wireless networks are analyzed and the energy consumption of MISO-based wireless networks is compared with conventional SISO-based wireless networks. Obtained results show the applicability of MISO system with Go-back-N ARQ technique in wireless networks with smart system design.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.4
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• pp.41-49
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• 2008

Sensor networks are often deployed in unattended environments, thus leaving these networks vulnerable to false data injection attacks in which an adversary injects forged reports into the network through compromised nodes. Such attacks by compromised sensors can cause not only false alarms but also the depletion of the finite amount of energy in a battery powered network. In order to reduce damage from these attacks, several security solutions have been proposed. Researchers have also proposed some techniques to increase the energy-efficiency of such security solutions. In this paper, we propose a CH(Cluster Header) selection algorithm to choose low power delivery method in sensor networks. The CNP(Contract Net Protocol), which is an approach to solve distribution problems, is applied to choose CHs for event sensing. As a result of employing CNP, the proposed method can prevent dropping of sensing reports with an insufficient number of message authentication codes during the forwarding process, and is efficient in terms of energy saving.