Recently, measuring instruments for SHM of structures has been developed. In general, the wireless transmission of sensor signals, compared to its wired counterpart, is preferable due to the absence of triboelectric noise and elimination of the requirement of a cumbersome cable. However, the low-cost wireless MEMS sensor has high noise density and transmits the signal wirelessly, so data transmission delay occurs during measurement. Therefore, the footbridges that was previously measured by a mobile phone in 2014 was remeasured using G-Link-200, iPad and iPhone to compare their performance.

A wireless sensor network is emerging technology and intelligent wireless communication paradigm that is dynamically aware of its surrounding environment. It is also able to respond to it in order to achieve reliable and efficient communication. The dynamical cognition capability and environmental adaptability rely on organizing dynamical networks effectively. However, optimally clustering the cognitive wireless sensor networks is an NP-complete problem. The objective of this paper is to develop an optimal sensor network design for maximizing the performance. This proposed Ranking Artificial Bee Colony (RABC) is developed based on Artificial Bee Colony (ABC) with ranking strategy. The ranking strategy can make the much better solutions by combining the best solutions so far and add these solutions in the solution population when applying ABC. RABC is designed to adapt to topological changes to any network graph in a time. We can minimize the total energy dissipation of sensors to prolong the lifetime of a network to balance the energy consumption of all nodes with robust optimal solution. Simulation results show that the performance of our proposed RABC is better than those of previous methods (LEACH, LEACH-C, and etc.) in wireless sensor networks. Our proposed method is the best for the 100 node-network example when the Sink node is centrally located.

해상에서 사용하고 있는 통신용 안테나는 눈에 띄게 계속 개발되고 있다. 하지만 해상통신용 안테나의 발전속도는 사용자의 요구와 비교했을 때 많이 부족한 것을 느끼고 있다. 그래서 해상에서 도움이 되는 안테나를 개발하고자 하였고 안테나의 소형화, 이득 및 방사패턴을 개선한 고속 통신망 시스템을 효과적으로 사용하기 위해 3 [GHz], 5.72 [GHz] 대역에서 동작하는 UWB/Bluetooth용 안테나를 설계하였다. 대역폭의 개선을 위해 마이크로스트립 패치 안테나를 선택하였고 3D 설계가 가능한 CST Microwave Studio 2014 프로그램을 이용하였다. 프로그램을 통해 각 단계마다 이론적인 근거에 의한 수식을 이용하여 슬롯의 폭, 길이, 전송선로의 폭 등을 계산하여 결과값을 확인하였다. 또한 시뮬레이션을 통해 제작 기준에 적합한 지 확인하는 과정을 거쳤다. 해상에서 근거리 통신을 위한 고속 무선 통신용인 UWB와 해당 기술을 쉽고 편하게 접할 수 있고 각각의 기기와 연결을 통해 근거리의 정보교환을 강조한 Bluetooth를 추가하여 사용자들에게 많이 활용될 수 있을 것이다.

Wireless sensors are more favorable in measuring structural response compared to conventional sensors. This is because they are easier to use with no issues with cables and are considerably cheaper. There are several applications that can be used in recording and analyzing data from MEMS sensor installed on an iPhone. The Vibration App is one of the applications used and there has not been adequate research conducted in analyzing the performance of this App. This paper analyzed the performance of the Vibration App by comparing it with the performance of an ICP sensor. Results show that natural frequency results are more accurate (error less than 5%) in comparison to the amplitude results. This means that built- in MEMS sensor in smartphones are good at estimating natural frequency of structures. In addition, it was seen that the results became more accurate at higher frequencies (5.0Hz and 10.0Hz).

Recently, measuring instruments for SHM of structures has been developed. In general, the wireless transmission of sensor signals, compared to its wired counterpart, is preferable due to the absence of triboelectric noise and elimination of the requirement of a cumbersome cable. However, in extreme environments, the sensor may be less sensitive to temperature changes and to the distance between the sensor and data logger. This may compromise on the performance of the sensor and instrumentation. Therefore, in this paper, free vibration experiments were conducted using wireless MEMS sensors at an actual site. Measurement was assessed in time and frequency domain by changing the temperature variation at(- 8℃, - 12℃ and - 16℃) and the communication distance (20m, 40m, 60m, 80m).

Currently, the commercialization of the 5th Generation (5G) service is becoming more prevalent in domestic communication network technology. This has reduced communication delay time and enabled large-capacity data transmission and video streaming services in real-time. In order to keep pace with these developments, K-water has introduced a smart process control system in water purification plants to monitor the status of the water purification process. However, since wireless networks are based on the public Long Term Evolution (LTE) network, communication delay time remains high, and high-resolution video services are limited. This is because communication networks still have a closed structure due to expense and security issues. Therefore, with 5G in its current form, it is very difficult to accommodate future services without improving the infrastructure of its communication networks. In recognition of these problems, this study implemented the authentication and management function of wireless networks on a wired network management system in the K-water Bansong water purification plant. The results confirmed that wired Local Area Network (LAN) services give a higher security performance than an expensive commercial wireless LAN system. This was achieved by using an Internet Protocol (IP) address management system of wired networks and the packet filtering function of the Layer2 (L2) switch. This study also confirmed that it is possible to create a wireless LAN service that is 3.7 times faster than the existing LTE communication network.

AIS는 상대선박의 식별 및 정보 등의 전송을 담당하는 주요 항해통신설비이지만, 최근 AIS 활용도의 증가로 과부하 문제 등 문제점이 대두되고 있다. 정부는 SMART-Navigation 사업 추진의 일환으로 연안 100 km에 무선 LTE망을 도입하는 계획을 수립 중에 있고 해양사고예방 및 환경보호 등 주요 목표를 달성하기 위해서는 이러한 Platform 위에 이용 가능한 서비스의 지속적인 개발·보급이 필요할 것이다. 본 연구에서는 이러한 서비스 개발의 기반이 될 수 있는 차량용 무선통신기술(WAVE)을 해상에 적용하고자 실선 해상실험을 통 해 WAVE 환경성능 평가를 실시하였다. 연구 수행 결과, 도로교통에서는 최대 1 km 내로 서비스가 제한되었지만 해상에서는 약 5마일 정 도의 통신범위에서 신뢰성 높은 Data 전송이 가능한 것으로 도출되었다. 이러한 실험 결과에 따라 추가적인 연구를 통해 충돌 회피 및 선박간 해양안전정보 전송 등 해양사고 예방에 WAVE 통신기술이 다양하게 활용 될 것으로 기대된다.

Recently, measuring instruments for SHM of structures had being developed. In general, the wireless transmission of sensor signals, compared to its wired counterpart, is preferable due to its absence of triboelectric noise and elimination of the requirement for cumbersome cable. However, the research on the tall buildings with relatively small vibration levels is insufficient. Therefore, in this paper, we used the wireless MEMS sensor and iPad to compare and analyze the vibration measurements of three tall buildings and two towers.

Wireless MEMS sensors have common features such as wireless communication, data measurement, embedded processing, battery-based self-power, and low cost, and increased measurement effectiveness. Wireless MEMS sensors enable efficient SHM without interfering with location because there is no requirement for triboelectric noise and cumbersome cables. However, there is little research on the communication distance with sensors and data. For instance, existing researches have limited communication distance experiments in civil engineering bridges. It is also necessary to investigate the characteristics of dynamic behavior and the communication distance of architectural structures with different wireless transmission/reception environments. Therefore, in a building structure with walls and slabs instead of open spaces, MEMS sensors and data loggers were used as distance experiments where communication disturbance between the vertical slab and the horizontal wall could actually be communicated.

도로를 통행하는 운전자는 경험에 의한 경로 선택을 하기에 앞서 실시간 교통정보를 활용하여 혼잡이 덜하고 목적지까지의 최소 소통 시간이 보장되는 경로를 활용하는 추세를 보이고 있다. 또한 교통 정보의 영향을 받는 산업이 점진적으로 증가함에 따라 교통 정보의 요구는 확대 일로에 있는 추세이다. 과히 스마트폰의 붐이라 할 정도로 스마트 기기의 보급이 증대하고 더불어서 모바일 콘텐츠의 요구는 점진적으로 확대되고 있으며, 다른 부문과 견주어서도 자동차와 연계된 교통정보의 요구는 과히 폭발적으로 증가하고 있다고 할 수 있다. 교통정보는 필수적으로 정보 신뢰성을 갖추어야 하며, 교통정보 수집을 위해 많은 교통 검지기의 설치가 요구되고 있다. 기존 교통정보의 수집은 교통 검지기를 설치하여 지점의 교통자료를 검지하는 지점 검지 방식이며, 루프 검지기, 레이더 검지기, 지자기 검지기 등이 있다. 지점 검지기는 설치된 지점의 교통 정보를 간단한 방식으로 실시간 검지한다는 장점이 있으나, 교차로, 일부 구간 정체 등 구간의 대표 교통정보를 위해서는 좁은 간격으로 설치하여야 하므로 많은 수량의 검지기가 요구된다. 그러므로, 구간 통행시간 측정이 가능한 구간 검지 방식으로 점진적으로 전환하고 있는 추세이다. 번호판 검지기(AVI), DSRC 검지기 등이 이러한 구간 검지 방식의 교통 검지기이다. 본 논문에서는 차량 내에 탑승자들이 소지한 스마트 기기의 블루투스, 와이파이 무선 통신 신호를 검지하여, 구간 검지 방식으로 무선신호 매칭을 통해 교통정보를 산출하는 교통정보 수집장치를 개발하였으며, 현장 평가를 수행하고 분석 결과를 제시하고자 한다. 스마트기기 무선신호를 활용한 교통정보 수집장치는 각 통신모듈에 유일한 Mac 주소를 수집 분석하는 방식을 사용한다. 그리고, 기존 교통검지기는 전기 및 유선통신 인프라를 기반으로 운영되어 이동성의 제약을 극복하고자 이동이 가능한 소형화 및 배터리 운영이 가능하도록 설계 제작하였다. 무전원 상태에서도 10일 이상의 운용이 가능하며, 소형화함에도 불구하고 기존 교통 검지기와 동등한 성능을 가지도록 개발 목표를 설정하였다. 이천시 곤지암IC 부근의 일반국도 3호선에서 두 조의 수집장치를 4km 간격으로 설치하여 오전 10시부터 7시간 현장 평가를 수행하였다. 전체 통행 차량의 30% 내외의 무선신호를 검지할 수 있었으며, 블루투스 무선신호보다 와이파이 무선신호가 3배 많은 빈도로 검지됨을 확인하였으며, 이로부터 산출된 통행시간은 비교적 현장 교통정보를 반영한 통행시간이 산출됨을 확인하였다. 개발된 교통정보 수집장치는 소형, 경량화 및 배터리 사용 설계를 통해 운영 환경에 영향받지 않고 간편하게 이동식으로 교통정보를 수집할 수 있음을 확인하였다. 사용자들의 스마트폰 사용 패턴으로 30% 정도만이 수집되었으나, 성능 지표 측면에서 고가의 교통 검지기를 대체할 수 있는 이동식 장비로서 운영이 가능함을 확인하였다.

Recently, measuring instruments for SHM of structures had being developed. In general, the wireless transmission of sensor signals, compared to its wired counterpart, is preferable due to its absence of triboelectric noise and elimination of the requirement for cumbersome cable. Preliminary studies on the continuous vibration measurement of high-rise buildings using MEMS sensors have been carried out. However, the research on the low-rise buildings with relatively small vibration levels is insufficient. Therefore, in this paper, we used the wireless MEMS sensor to compare and analyze the vibration measurements of three low-rise buildings.

In mobile communication systems, location management deals with the location determination of users in a network. One of the strategies used in location management is to partition the network into location areas. Each location area consists of a group of cells. The goal of location management is to partition the network into a number of location areas such that the total paging cost and handoff (or update) cost is a minimum. Finding the optimal number of location areas and the corresponding configuration of the partitioned network is a difficult combinatorial optimization problem. This cell grouping problem is to find a compromise between the location update and paging operations such that the cost of mobile terminal location tracking is a minimum in location area wireless network. In fact, this is shown to be an NP-complete problem in an earlier study. In this paper, artificial bee colony (ABC) is developed and proposed to obtain the best/optimal group of cells for location area planning for location management system. The performance of the artificial bee colony (ABC) is better than or similar to those of other population-based algorithms with the advantage of employing fewer control parameters. The important control parameter of ABC is only ‘Limit’ which is the number of trials after which a food source is assumed to be abandoned. Simulation results for 16, 36, and 64 cell grouping problems in wireless network show that the performance of our ABC is better than those alternatives such as ant colony optimization (ACO) and particle swarm optimization (PSO).

The electromagnetic interference(EMI) shielding sheet of grid pattern for the wireless charger has been designed by using grid pattern metal sheet, PET & DST stacking and laminating technology. For this purpose, the twisting protection and the bubbling prevention device, the automatic position adjustment controller, the visual sensors and the motor actuator for controller, the EMI shielding sheet cutting device and the main control system have been developed for manufacturing the apparatus. As the study result, the development on manufacturing the equipment and shielding sheet of the EMI shielding sheet of grid pattern for the wireless charger having the lamination productivity of 27.4m/min exceeded the target of 8m/min in this study. In addition, the magnetic induction and the applicable shielding sheet were prepared in the magnetic resonance system, all of the two wireless charging system. The power with a band of average 6.87MHz of shielding sheet was greater than the target of 30dB to 32.57dB. The available frequency with a band of average 7.95MHz the target was exceeded by a 7.00MHz.