Wireless sensor systems are primarily used for monitoring natural environments or industrial automation. The physical environment where these systems are installed is often unstable, making it difficult to replenish sensor energy immediately. Complex and harsh conditions can impact the network's structure, affecting monitoring performance. Wireless sensor systems consist of hundreds of sensors that collect data from hazardous environments and transmit information to a central system. However, due to the system's physical structure, information delays or losses may occur. This paper proposes a distance-based tree structure to address these issues in wireless sensor systems, and experimental results confirm its superior performance.

스마트팜 요소들 중에서 중요한 요인 중 하나는 환경 계측이 다. 본 연구에서는 오픈 소스 프로그램인 아두이노, 앱 인벤터 와 노드 레드를 이용하여 로라와 블루투스 무선 통신을 통한 환 경 계측 모니터링 시스템을 설계하였다. 이 시스템은 아두이 노, 로라 쉴드, 온습도 센서(SHT10), 이산화탄소 센서(K30) 로 구성되었다. 아두이노(Arduino) 프로그램에서 사용된 라 이브러리로는 LoRa.h, Sensirion.h, LiquidCrystal_I2C.h와 K30_I2C.h를 사용하였다. 일정한 주기로 센서에서 환경 데 이터를 받을 때, 데이터의 안정화를 위해 평균값을 사용한 코 딩을 사용하였다. 사용자 인터페이스로 노드 레드와 앱 인벤 터 프로그램을 이용하여 안드로이드 기반의 앱을 개발하였다. 아두이노의 시리얼 화면과 스마트 폰의 화면 및 노드 레드의 사용자 인터페이스에 출력되는 화면으로 센서에 위한 환경 자 료가 잘 수집되어 디스플레이되는 것을 볼 수 있었다. 이러한 오픈소스 기반의 플랫폼과 프로그램들은 다양한 농업 응용 분 야에 적용될 것이다.

국내 고도성장기 이후 본격 건설되기 시작한 사회 기반 시설물은 노후화가 빠르게 진행되고 있다. 특히 사고 발생 시 대량 인명 피해로 직결될 수 있는 교량, 터널 등의 대형 구조물에 대한 안전성 평가가 필요하다. 하지만 기존의 유선 센서 기반의 Structural Health Monitoring(SHM)을 개선한 무선 스마트 센서 네트워크는 짧은 신호 도달거리로 인해 경제적이고 효율적인 시스템 구축이 힘들다. 따라서 LoRa LPWAN 시스템은 사물인터넷의 확산과 더불어 저전력 장거리 통신이 각광을 받고 있으며, 이를 구조 건전성 모니터링에 응용함으로써 경제적이면서도 효율적인 모니터링 시스템 구축이 가능하다. 본 연구에서는 LoRa LPWAN 기반의 무선 계측센서 기술 동향을 조사하였으며, LoRa LPWAN 기반의 무선 계측센서 설치 및 유지관리 방안을 제안한다.

Information and communication technologies are developing rapidly as IC chip size becomes smaller and information processing becomes faster. With this development, digital circuit technology is being widely applied to mobile phones, wireless LANs, mobile terminals, and digital communications, in which high frequency range of GHz is used. In highdensity electronic circuits, issues of noise and EMC(Electro-Magnetic Compatibility) arising from cross talk between interconnects or devices should be solved. In this study, sheet-type electromagnetic wave absorbers that cause electromagnetic wave attenuation are fabricated using composites based on soft magnetic metal powder and silicon rubber to solve the problem of electromagnetic waves generated in wireless communication products operating at the frequency range of 2.4 GHz. Sendust(Fe-Si-Al) and carbonyl iron(Fe-C) were used as soft magnetic metals, and their concentrations and sheet thicknesses were varied. Using soft magnetic metal powder, a sheet is fabricated to exhibit maximum electromagnetic attenuation in the target frequency band, and a value of 34.2dB(99.9 % absorption) is achieved at the target frequency.

The ship steering is a very important factor for safe operation. Recently, the ship is controlled in a space other than the wheelhouse through the wired controller. However, there has been a continuing need to improve the inconvenience of wired systems. In this study, a system to control the steering angle and throttle of ship by RF communication method was developed and applied to actual ship. Since the reliability is secured through the safety evaluation, the wireless steering system improves the convenience and economic efficiency of ship steering.

Wireless sensors are more favorable in measuring structural response compared to conventional sensors in terms of them being easier to use with no issues with cables and them being considerably cheaper. Previous tests have been conducted to analyze the performance of MEMS (Micro Electro Mechanical Systems) sensor in sinusoidal excitation tests. This paper analyzes the performance of in-built MEMS sensors in devices by comparing with an ICP sensor as the reference. Earthquake input amplitude excitation in shaking table tests was done. Results show that MEMS sensors are more accurate in measuring higher input amplitude measurements which range from 100gal to 250gal than at lower input amplitudes which range from 10gal to 50gal. This confirms the results obtained in previous sinusoidal tests. It was also seen that natural frequency results have lower error values which range from 0% to 3.92% in comparison to the response spectra results. This also confirms that in-built MEMS sensors in mobile devices are good at estimating natural frequency of structures. In addition, it was also seen that earthquake input amplitudes with more frequency contents (Gyeongju) had considerably higher error values than Pohang excitation tests which has less frequency contents.

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.

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.

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.

Introduction In an age of rapid development at the information technology front, the viability of ‘smart travel destinations’ is increasingly becoming a reality (Buhalis & Amaranggana, 2014, 2015). Advances in mobile technology have allowed travel destinations to leverage the location-based wireless tracking capabilities afforded by 3/4G telecommunication networks, Bluetooth connectivity, GPS and Wi-Fi networks (Choe & Fesenmaier 2017; Eriksson, 2002). The benefits of these wireless tracking technologies include precise information on spatial behaviour (Edwards, Dickson, Griffin, & Hayllar, 2010), relevant location-based services (LBS)(Pedrana, 2014), navigational services (Eriksson, 2002), as well as recommender services (Tussyadiah & Wang, 2016). With this kind of data available to them, destination management organisations (DMOs) are able to develop more customise tourist engagement strategies which will help them communicate specifically tailored results to tourists (Edwards & Griffin, 2013). While the focus of current tourism research has been the benefits of these wireless tracking technologies (WTTs) to the destination, little research has been done to examine tourists’ perceptions of these technologies. The current exploratory study will investigate tourist perceptions of three prominent kinds of WTTs with differing levels of control at a travel destination: (1) wireless tracking only (WT only; low control); (2) Wi-Fi wireless tracking (Wi-Fi WT; moderate control); and (3) application-based tracking (App; high control). Theoretical development The current study applies the Expectancy-Value Theory in examining tourist perceptions of WTTs at a travel destination. The Expectancy-Value Theory suggests that motivation for a behaviour is determined by the desirability of the outcome i.e. benefits to the tourist (Sparks, 2007). In the context of this study, perceived personalisation and perceived innovativeness serve as benefits to tourists. Perceived personalisation is defined as the ability of a DMO to recognize and treat its tourists as individuals through personal messaging, targeted banner ads, special offers on bills, or other personal transactions” (Imhoff, Loftis, & Geiger, 2001). Perceived innovativeness reflects the degree to which a new product is seen to possess new and unique attributes and features (Fu, Jones, & Bolander, 2008). Studies have shown that perceived personalisation and perceived innovativeness positively impact on attitudes toward the product (Baek & Morimoto, 2012; Fu & Eliott, 2013), which in the context of this study relates to both the WTT itself as well as the destination. However, mere presence of WTTs can often provoke concerns about manipulative intent (Lee-Wingate & Xie, 2010) and privacy (Shilton, 2009). Inferences of manipulative intent is defined as tourist perceptions that a company is attempting to persuade via inappropriate, unfair or manipulative means (Campbell, 1995). Privacy concerns refer to the degree to which a tourist is worried about the potential invasion of the right to prevent the disclosure of personal information to others (Baek & Morimoto, 2012, p. 63). Inferences of manipulative intent and privacy concerns have been found to negatively impact on attitudes toward the product (Lee-Wingate & Xie, 2010; Shilton, 2009). Thus, the ability of a travel destination to emphasise the pros and minimise concerns for the cons of WTTs will result in more positive attitudes towards the WTT as well as the destination, which in turn, will positively impact on intention to visit the destination (based on arguments in tourism research suggesting that both attitudes toward products and the destination itself may have an impact on intention to visit e.g. Elliot, Papadopoulos & Kim 2011; Lee & Lockshin 2012). The hypothesised model for this study can be seen in Figure 1. Methodology The conceptual model was tested using data from the United States via the Amazon Mechanical Turk (MTurk) platform. A total of 750 responses were acquired but only 615 were included for analysis (responses were excluded due to incomplete data or straight-lining). A between-subjects experimental design was implemented respondents viewing a stimulus for either (1) wireless tracking only (WT only; low control); (2) Wi-Fi wireless tracking (Wi-Fi WT; moderate control); or (3) application-based tracking (App; high control). A pretest of the stimulus confirmed the levels of control proposed by the researchers. Respondents were first told to imagine their next travel destination and were then shown a stimulus. In the WT only condition, respondents were told that the destination was tracking the movement of tourists when their smartphones wireless, Bluetooth or mobile reception was turned on. In the Wi-Fi WT condition, respondents were informed that the destination would track tourists logged on to the destination’s Wi-Fi network. In the App condition, respondents were notified that the destination has an app system which allows the destination to track tourists and send them personalised push notifications. The difference between these three conditions was the level of perceived control that tourists had over the tracking of their location within the destination. Respondents then rated the WTT and destination with regards to inferences to manipulative intent, privacy concerns, perceived personalisation, perceived innovativeness, attitude toward the WTT, attitude toward the destination, and intention to visit the destination. The measures for each of these scales were chosen for their reliability and relevance to the current study. Structural equation modelling then examined the hypothesised relationships for significance. Results and discussion Exploratory and factor analysis was conducted to ensure the unidimensional of the scales. Composite reliabilities ranged from 0.70 to 0.95 and the average variance extracted scores ranged from 0.70 to 0.87, suggesting strong internal validity for all scales. All measures were also tested for convergent and discriminant validity which were both supported. Then, the hypotheses were examined using a multigroup analysis with structural equation modelling in AMOS 22. The goodness-of-fit indices for the structural model was deemed acceptable (χ²/df=1.67; RMSEA=0.03; CFI=0.97; NFI=0.94; IFI=0.90) (model comparisons revealed no significant differences at a model level suggesting that the model applied across the different groups). The results of the path analysis revealed five hypotheses which were fully supported (H1a, H2a, H3a, H3b and H6b). The remaining six hypotheses (H1b, H2b, H4a, H4b, H5 and H6a) were only partially supported with significant parameter estimates noted for either one or two of the conditions. The full result of the path analysis can be seen in Table 1. The results suggest that inferences of manipulative intent significantly decreased attitude toward the WTT, highlighting the need for destinations to be transparent about the reasons for tracking tourists. Specifically, the concealed tracking of tourists’ movements was particularly damaging to attitude toward the destination. Privacy concerns also negatively impacted on attitude toward the WTT for all conditions, but surprisingly privacy concerns appeared to significantly increase attitude toward the destination under the App condition. A potential explanation for this is the fact that despite potential for privacy infringements, tourists possess control over usage of the application, thereby moderating the ability of the destination to track them. However, this result warrants greater investigation in future studies. Perceived personalisation was noted to positively impact on attitudes toward the WTT and destination suggesting that tourists positively regarded the benefits of personalisation that the WTT afforded them. Further, perceived innovativeness appeared to positively impact on attitude towards the WTT for the App condition, but more interestingly, positively impacted on attitude toward the destination for the WT only condition. This may potentially suggest that while tourists did perceive manipulative intent in the wireless tracking of their whereabouts they also perceived this to be an innovation. Theoretically, this study extends the tourism literature with regards to the installation or application of wireless tracking technologies. It highlights the aspects that appeal to tourists as well as the concerns that they may have. From a managerial perspective, the results suggest a need for transparency as well as the empowerment of tourists to choose the degree to which their whereabouts are tracked within the destination. It offers further insights into which technologies are best suited to be leveraged in order to develop stronger tourist engagement at the destination. The implications of these results apply to destination managers, marketers as well as policy makers. A successful balance between obtaining valuable information about tourists and providing them with a choice whether or not to be tracked is crucial in ensuring favourable perception of the travel destination.

Over the past decade, the advances in the Internet of Things has allowed WiFi infrastructure to track the movement and location of smart devices. This innovative technology is sometimes referred to as wireless analytics or offline / in-store visitor analytics. Similar to an offline or instore version of website analytics, wireless analytics can infer instore shopping behavior from analyzing the dwell time, movement, and behavior of a smart device within a designated vicinity. The study was carried out at an activation area of food trucks at an Australian metropolitan university. Visitor analytics were gathered by using a wireless analytic modem that was configured to ping and pick up wireless signal emitted by smart devices within the radius of the food truck area. Challenging past research on pop-stores, our findings show that novelty of pop-up food trucks may not necessarily predict their success and consumers tend to prefer familiar food trucks at the Australian metropolitan university. In fact, the presence of novel food trucks may encourage consumers to walk-by without any interaction with the food trucks.