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To provide diverse in-home services like elderly care, versatile activity recognition technology is essential. Radio-based methods, including WiFi CSI, RFID, and backscatter communication, are preferred due to their minimal privacy intrusion, reduced physical burden, and low maintenance costs. However, these methods face challenges, including environmental dependence, proximity limitations between the device and the user, and untested accuracy amidst various radio obstacles such as furniture, appliances, walls, and other radio waves. In this paper, we propose a frequency-shift backscatter tag-based in-home activity recognition method and test its feasibility in a near-real residential setting. Consisting of simple components such as antennas and switches, these tags facilitate ultra-low power consumption and demonstrate robustness against environmental noise because a context corresponding to a tag can be obtained by only observing frequency shifts. We implemented a sensing system consisting of SD-WiFi, a software-defined WiFi AP, and physical switches on backscatter tags tailored for detecting the movements of daily objects. Our experiments demonstrate that frequency shifts by tags can be detected within a 2 m range with 72% accuracy under the line of sight (LoS) conditions and achieve a 96.0% accuracy (F-score) in recognizing seven typical daily living activities with an appropriate receiver/transmitter layout. Furthermore, in an additional experiment, we confirmed that increasing the number of overlaying packets enables frequency shift-detection even without LoS at distances of 3–5 m. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2006.03.011 Byline: Hirozumi Yamaguchi (a), Khaled El-Fakih (b), Gregor v. Bochmann (c), Teruo Higashino (a) Keywords: Petri net; Distributed system; Specification; Automated design Abstract: We consider the derivation of a protocol specification from a service specification written in Predicate/Transition-nets (Pr/T-nets). The service specification describes the global behavior of a system and includes the allocation of the Pr/T-net places to N distributed sites. The paper presents a new algorithm for deriving a protocol specification that defines the behavior of N communicating entities that execute on the N sites and coordinate their actions in order to conform to the global behavior defined by the service specification. Our algorithm decomposes each transition of the service specification into a set of communicating Pr/T-subnets running on the N entities. Moreover, for efficiently controlling the conflict for shared resources, we present a timestamp-based contention control algorithm and incorporate it into the derivation algorithm. A tool has been developed that implements our algorithm and works together with other existing tools for the graphical representation of the service and derived protocol specifications. Two application examples are discussed. Author Affiliation: (a) Graduate School of Information Science and Technology, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan (b) School of Engineering, American University of Sharjah, Sharjah, P.O. Box 26666, United Arab Emirates (c) School of Information Technology and Engineering, University of Ottawa, 800 King Edward Avenue, Ottawa, Ont., Canada K1N 6N5 Article History: Received 16 June 2005; Revised 19 December 2005; Accepted 16 March 2006 Article Note: (miscellaneous) Responsible Editor: Juan Quemada

Building energy management systems (BEMSs) have been successfully adopted as key control units for modern structures to maintain energy efficiency and provide a comfortable thermal environment for occupants. Recent advances in information and communication technology toward “Industry 4.0” are enhancing the utility of BEMSs. However, challenges, such as how to process the exponentially growing amount of heterogeneous data generated in buildings, need to be addressed to realize “Building 4.0,” which encompasses next-generation smart systems that provide user-centric services. In this article, we propose BEMS–Edge, a framework that integrates seamless, real-time information acquisition, transmission, interpretation, and action in intelligent BEMSs. The primary components, including the Internet of Things (IoT), cloud/edge computing, big data analytics, and artificial intelligence (AI), converge to create a data-driven edge computing fabric offering a range of benefits, such as real-time data analytics and cost savings. The effectiveness of BEMS–Edge is verified by an established, real-world BEMS testbed. [ABSTRACT FROM AUTHOR]

This study aimed to clarify the adaptation features of University students exposed to fully online education during the novel coronavirus disease 2019 (COVID-19) pandemic and to identify accompanying mental health problems and predictors of school adaptation. The pandemic has forced many universities to transition rapidly to delivering online education. However, little is known about the impact of this drastic change on students' school adaptation. This cross-sectional study used an online questionnaire, including assessments of impressions of online education, study engagement, mental health, and lifestyle habits. In total, 1,259 students were assessed. The characteristics of school adaptation were analyzed by a two-step cluster analysis. The proportion of mental health problems was compared among different groups based on a cluster analysis. A logistic regression analysis was used to identify predictors of cluster membership. P -values < 0.05 were considered statistically significant. The two-step cluster analysis determined three clusters: school adaptation group, school maladaptation group, and school over-adaptation group. The last group significantly exhibited the most mental health problems. Membership of this group was significantly associated with being female (OR = 1.42; 95% CI 1.06–1.91), being older (OR = 1.21; 95% CI 1.01–1.44), those who considered online education to be less beneficial (OR = 2.17; 95% CI 1.64–2.88), shorter sleep time on weekdays (OR = 0.826; 95% CI 0.683–.998), longer sleep time on holidays (OR = 1.21; 95% CI 1.03–1.43), and worse restorative sleep (OR = 2.27; 95% CI 1.81–2.86). The results suggest that academic staff should understand distinctive features of school adaptation owing to the rapid transition of the educational system and should develop support systems to improve students' mental health. They should consider ways to incorporate online classes with their lectures to improve students' perceived benefits of online education. Additionally, educational guidance on lifestyle, such as sleep hygiene, may be necessary. [ABSTRACT FROM AUTHOR]

Several attempts have been made to grasp three‐dimensional (3D) ground shape from a 3D point cloud generated by aerial vehicles, which help fast situation recognition. However, identifying such objects on the ground from a 3D point cloud, which consists of 3D coordinates and color information, is not straightforward due to the gap between the low‐level point information (coordinates and colors) and high‐level context information (objects). In this paper, we propose a ground object recognition and segmentation method from a geo‐referenced point cloud. Basically, we rely on some existing tools to generate such a point cloud from aerial images, and our method tries to give semantics to each set of clustered points. In our method, firstly, such points that correspond to the ground surface are removed using the elevation data from the Geographical Survey Institute. Next, we apply an interpoint distance‐based clustering and color‐based clustering. Then, such clusters that share some regions are merged to correctly identify a cluster that corresponds to a single object. We have evaluated our method in several experiments in real fields. We have confirmed that our method can remove the ground surface within 20 cm error and can recognize most of the objects. [ABSTRACT FROM AUTHOR]

Despite recent advances in localization technology for mobile devices, to provide real-time position information to people indoors is still a big challenge; usually there is a trade-off between localization accuracy and infrastructural costs (e.g., dense anchor deployment). A possible solution would be employing cooperative approaches which utilize estimated positions of surrounding mobile nodes to complement a small number of anchors. However, it often results in poor estimation accuracy since a temporary large position error due to node mobility easily propagates to neighbor nodes. This paper presents a novel cooperative localization algorithm that addresses this problem by focusing on “stop-and-go behavior” of indoor pedestrians. The key idea is to collaboratively find movement state (moving or static) of each node based on peer-to-peer distance measurement which is inherently necessary for cooperative localization, and use only static nodes as reference points for localization to avoid potential accuracy deterioration. Also, nodes in static state can reduce localization frequency to conserve battery power, keeping the tracking quality. Through extensive simulations, we have demonstrated the performance of our method in terms of accuracy and energy efficiency. The effectiveness in a real application scenario has been also confirmed using a measurement-based sensor model and real mobility traces. [ABSTRACT FROM AUTHOR]

We propose an opportunistic ad hoc localization algorithm called Urban Pedestrians Localization (UPL), for estimating locations of mobile nodes in urban districts. The design principles of UPL are twofold. First, we assume that location landmarks are deployed sparsely due to deployment-cost constraints. Thus, most mobile nodes cannot expect to meet these location landmarks frequently. Each mobile node in UPL relies on location information received from its neighboring mobile nodes instead in order to estimate its area of presence in which the node is expected to exist. Although the area of presence of each mobile node becomes inexact as it moves, it can be used to reduce the areas of presence of the others. Second, we employ information about obstacles such as walls, and present an algorithm to calculate the movable areas of mobile nodes considering obstacles for predicting the area of presence of mobile nodes accurately under mobility. This also helps to reduce each node's area of presence. The experimental results have shown that UPL could be limited to $(0.7r)$ positioning error in average, where $(r)$ denotes the radio range by the above two ideas. [ABSTRACT FROM PUBLISHER]

Recently, considerable research has been focused on applying ad hoc wireless networking technology to on-the-move vehicles. In this paper, we focus on distributed detection of dangerous vehicles on roads and highways.We propose the dangerousvehicle-detection protocol (DVDP) to detect drivers who violate the permitted speed limit. In DVDP, each vehicle collects surrounding vehicles' identifications (IDs) and propagates warning information (including its position, speed, time, and collected IDs). This information is then forwarded hop-by-hop using ad hoc communications. A vehicle that receives this information will start to observe its surrounding vehicles. If surrounding vehicles are identified in the received warning information, it will estimate the speed of such vehicles. If the estimated speed exceeds the permitted speed, such vehicles are then marked as "suspected vehicles," and the updated warning information is further propagated. By repeating this process, the suspected vehicle (where other vehicles observe the speed violation) will ultimately be marked as a "dangerous vehicle." This judgment is then further propagated to warn others and to inform the traffic police. We evaluated the performance of DVDP using a simulator that performs both macroscopic and microscopic traffic simulation, taking into account realistic lane and speed models, mobility, position, and location errors. Simulation results revealed that DVDP's detection probability is greater than 80% when vehicle density is above 40 vehicles/min. When vehicle density is low, deployment of relay points can help to further improve detection probability. In addition, by utilizing vehicles in opposite lanes, detection probability can be further improved. [ABSTRACT FROM AUTHOR]

Studies of facial parts have been conducted in recent years in various fields of medical science and psychology, including studies of the lip contour and location. In fact, in the treatment of cleft lip patients in oral surgery, it is desirable to extract the precise lip contour and to identify its location on the face in order to plan the plastic surgery procedure and to follow up the site after surgery. Aiming at applications to dental treatment, in this study we attempt to extend the lip contour extraction procedure based on the deformable template to the case of a template with left– right asymmetry. An algorithm is also proposed for adjusting the hue and value thresholds in order to improve extraction accuracy and reduce the burden on the user. The proposal is evaluated using sample images of normal subjects and cleft lip patients. It is shown that the shape and location of the lip can be extracted precisely and automatically by the proposed method. In connection with application to dental clinics, we present an example of a quantitative evaluation of the lip shape by using the parameters extracted by the proposed method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(5): 80– 89, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10668 [ABSTRACT FROM AUTHOR]

In wavelength division multiplexing (WDM) technology, high-speed large-capacity communication is realized by transmitting multiple optical signals with different wavelengths in parallel on an optical fiber. In WDM technology, the logical topology of the network can generally be modified by changing the wavelength assignment to the transmitters and receivers. Thus it is important to develop an algorithm that derives the wavelength assignment that maximizes the transmission efficiency of the network. This paper considers a bidirectional Manhattan street network which has a regular topology, and proposes a hierarchical two-stage heuristic algorithm. In the first stage, the initial solution is derived by hierarchical region division and node assignment to the regions. In the second stage, the solution is improved by simulated annealing (SA). The proposed algorithm is evaluated by simulations of random instances and instances for which optimal solutions are already known. The effectiveness of the proposed algorithm is demonstrated through comparisons to the existing one. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(4): 74–83, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10534 [ABSTRACT FROM AUTHOR]

In this paper, we propose a new protocol that constructs a spanning tree on an overlay network given by a complete graph, in a decentralized manner. This algorithm consists of two decentralized operations, which support joining of and leaving of the overlay network at any time in the session (though there are some constraints). Whenever a node joins or leaves, the rest of the nodes (or node itself in case of join) can be repositioned (or positioned) to minimize the maximum delay from a certain set of nodes in the current tree without violating the degree constraint at each node, by applying these operations. We have confirmed the usefulness of this algorithm by performing simulation and real-world experiments. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(14): 15–24, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20655 [ABSTRACT FROM AUTHOR]

In the development of real-time communicating hardware/embedded-software systems, it is frequently the case that we want to refine/optimize the system's internal behavior while preserving the external timed I/O behavior. In such a design refinement, modification of the systems' internal branching structures, as well as re-scheduling of internal actions, may frequently occur. Our goal is, then, to ensure that such modification of internal branching structures and re-scheduling of internal actions preserve the systems' external timed behavior, which is typically formalized by the notion of (timed) failure equivalence since it is less sensitive to the difference of internal branching structures than (timed) weak bisimulation. In order to know the degree of freedom of such re-scheduling, parametric analysis is useful. One of the models suitable for such an analysis is a parametric time-interval automaton(PTIA), which is a subclass of the existing model, a parametric timed automaton. It has only a time interval with upper- and lower-bound parameters as a relative timing constraint between consecutive actions. In this paper, at first, we propose an abstraction algorithm of PTIA which preserves timed failure equivalence. Timed failure equivalence is strictly weaker than timed weak bisimulation in the sense that it does not distinguish the difference of the timing when the internal resolution of nondeterminism has occurred, but it does distinguish the difference of the refusals of communicating actions observed by an external environment. Then, we also show that after applying our algorithm, the reduced PTIA has no internal actions, and thus the problem deriving a parameter condition in order that given two models are timed failure equivalent can be reduced to the existing parametric strong bisimulation equivalence checking. [ABSTRACT FROM AUTHOR]

We propose a symbolic model checking algorithm for a class of extended finite state machines equipped with integer variables (FSM/int). An FSM/int has several constraints on variable assignments, such as a variable of FSM/int keeps its value until the control visits at the definition transition and new value is fed via external input. Our model checking algorithm verifies whether an FSM/int satisfies a property described in CTL-like expressions over integer variables. We have implemented a model checker, and verified that blackjack dealer circuits and a packet multiplex protocol satisfy some designated properties. We have found that the verification of systems with 100 states and 10 integer variables can be carried out in a few seconds in most cases (in the worst case, a few minutes). © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(6): 64–72, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20264 [ABSTRACT FROM AUTHOR]

The specification for a communication protocol is generally represented by a finite-state machine, and the operation of the machine is represented by transitions among states. The device implementing such specification is called the implementation under test (IUT). It is important for the IUT that its operation should be verified for all state transitions on the finite-state machine given in the specification. This test is called the conformance testing. In such testing it is important to generate efficiently a route containing all state transitions from the initial state. This problem is called the test sequence generation problem. This paper considers the test sequence generation problem for a communication protocol and proposes an application of an algorithm for satisfiability problem (SAT) that can flexibly handle various constraints, such as the order constraint and the time constraint among multiple constraints. The proposed method is applied to the dynamic host configuration protocol (DHCP) and its effectiveness is demonstrated. © 2003 Wiley Periodicals, Inc. Syst Comp Jpn, 34(11): 20–29, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10482 [ABSTRACT FROM AUTHOR]

Protocol synthesis is used to derive a protocol specification, that is, the specification of a set of application components running in a distributed system of networked computers, from a specification of services (called the service specification) to be provided by the distributed application to its users. Protocol synthesis reduces design costs and errors by specifying the message exchanges between the application components, as defined by the protocol specification. In general, maintaining such a distributed application involves applying frequent minor modifications to the service specification due to changes in the user requirements. Deriving the protocol specification after each modification using the existing synthesis methods is considered expensive and time consuming. Moreover, we cannot identify what changes we should make to the protocol specification in correspondence to the changes in the service specification. In this paper, we present a new synthesis method to re-synthesize only those parts of the protocol specification that must be modified in order to satisfy the changes in the service specification. The method consists of a set of simple rules that are applied to the protocol specification written in an extended Petri net model. An application example is given along with some experimental results. [ABSTRACT FROM AUTHOR]

This paper considers the extended finite-state machine model (EFSM/Pres), which has several registers to retain integer values, in addition to the controller of the finite-state machine. A new method is proposed for automatically generating the test sequence for the conformance test, called the E-UIO sequence, from the formal specification of the communication protocol written by that model. In EFSM/Pres, the data type to be handled is restricted to the integer type. The condition for each transition is described by a logical expression composed of addition/subtraction and comparison of integers. For this class, the input/output sequence composed of the UIO sequence and its precedence sequence is considered. By inputting adequate values to the input variables of the sequence, if the input/output sequences are executable regardless of the register values at the start state of the precedence sequence, that input/output sequence is called an E-UIO sequence. The existence of the state to be recognized is verified by using the E-UIO sequence. If the given UIO sequence is executable, an E-UIO sequence containing the definite input values is always generated automatically. A method to generate automatically a test sequence that verifies the validity of the transition is also proposed. As an example, the proposed method is applied to the OSI session protocol. © 1999 Scripta Technica, Electron Comm Jpn Pt 1, 82(10): 50–60, 1999 [ABSTRACT FROM AUTHOR]

It is well known that algebraic specification methods are promising for specifying programs and for verifying their various properties formally. In this paper, an algebraic specification of information transfer procedures of high-level data link control (HDLC) procedures is presented and some of the main properties of the specification arc shown. First, we introduce abstract states, state transition functions, and output functions corresponding to elementary notions extracted from the description of HDLC procedures in ISO 3309-1979 (F) and ISO 4335-1979 (E). Second, we show axioms which represent the relations between the values of functions before and after the state transitions. Then, it is proved that the specification is "consistent," "sufficiently complete," and "nonredundant." Also it is shown that an implementation which realizes the specification is naturally derived. In the last section, verification of various properties of HDLC procedures is formulated in the same framework as the algebraic specification, and some verification examples are presented. [ABSTRACT FROM AUTHOR]

It is known as generally impossible to generate automatically the test cases for arbitrary LOTOS expression containing data parameters. A subclass of LOTOS, called P-LOTOS, is defined. In P-LOTOS, the data type is restricted to be integer and Boolean and the operation on the integer is restricted to be the addition/subtraction and comparison. This paper presents an algorithm for automatic generation of the test cases for this class of LOTOS descriptions. Algorithms also are presented solving the detection problems for the deadlocks, the unexecutable edges, sad the nondeterministic branches, The proposed algorithm is applied to a simplified OSI session protocol, and the result is reportod in this paper. [ABSTRACT FROM AUTHOR]

In this paper, new methods for providing the correctness of refinement among abstract sequential machine style programs are described. The programs are described in algebraic language ASL using some useful notions, i.e., the extended projection and the valid teachability condition for each transition function. These notions allow a designer to refine a given text (program or specification) to a concrete text more freely than the text that does not use such notions. These notions can also enhance the expressive power of the text. On the other hand, these advantages would have lost half their values, if useful methods to prove the correctness of refinement among the texts using them are not found. Thus new methods for proving the correctness of the texts are proposed, and they do not require much proof loads. First, the correctness of refinement among the ASL texts with the extended projection is defined. Second, a method is proposed for proving the correctness of refinement among such texts. Also proposed is a definition of the correctness of refinement among the texts with the valid reachability conditions and a method to prove their correctness. These methods do not require more proof loads than the usual methods for the texts that do not use such notions in the abstract sequential machine style. Therefore, these methods are useful. [ABSTRACT FROM AUTHOR]

This paper describes the algebraic specification with a high degree of abstraction for the token ring LAN protocol provided in IEEE standard 802.5. Then the anticipated properties are verified by an algebraic method, the specification satisfies the safeness property (any frame transmitted from the active station either has been received by all stations or received by consecutive stations in the downstream without an error) and the mutual exclusion property (there exists one and only one token on the ring). The verification is carried out interactively using the verification support system. The process of selecting the lemmas to be introduced, the process of verification, CPU time used for the verification and the number of days needed in the verification are discussed. [ABSTRACT FROM AUTHOR]

This paper considers the communication protocol whose specification is described algebraically in a style of an "abstract sequential machine." A method is presented to verify the progress property of the protocol, such that the transmitted data will eventually be received. First, by the algebraic method, we verify some static properties (invariants) which hold in any state reachable by the execution of the state transitions permitted by the protocol. Also, we verify the relations which hold between the states before and after the execution of each state transition. These relations are transformed into the formulas of the temporal logic by using some transformation rules. At the same time, the formulas of the temporal logic are provided as the assumptions for the stations and communication lines, which are needed in the discussion of progress property of the protocol, such that the communication lines are not functionally cut off. Using these formulas and standard axioms in the temporal logic (inference rules), it is shown that the predicates representing the progress property of the protocol are true. The foregoing is the outline of the discussions in this paper. This paper applies the method to Stenning's data transfer protocol, and the progress property is verified. [ABSTRACT FROM AUTHOR]

Some methods for synthesizing a protocol specification from a given service specification have been proposed using various computational models. However, the existing methods cannot treat service specifications including both complex control flows and system variables. In this paper, we propose a method for synthesizing a protocol specification automatically from a pair consisting of a service specification and a resource allocation. In our method, service specifications are described in an extended model of Petri nets, which can treat system variables. We have developed a pair consisting of a synthesis system and an execution system, and applied them to CSCW (Computer Supported Cooperative Work). © 1998 Scripta Technica, Electron Comm Jpn Pt 3, 81(8): 18–26, 1998 [ABSTRACT FROM AUTHOR]

Thermal images are widely used for various healthcare applications and advanced research. However, thermal images captured by smartphone thermal cameras are not accurate for monitoring human body temperature due to the small body that is vulnerable to temperature change. In this paper, we propose ThermalWrist, a dynamic offset correction method for thermal images captured by smartphone thermal cameras. We fully utilize the characteristic that is specific to thermal cameras: the relative temperatures in a single thermal image are highly reliable, although the absolute temperatures fluctuate frequently. To correct the offset error, ThermalWrist combines thermal images with a reliable absolute temperature obtained by a wristband sensor based on the above characteristic. The evaluation results in an indoor air-conditioned environment shows that the mean absolute error and the standard deviation of face temperature measurement error decrease by 49.4% and 64.9%, respectively. In addition, Pearson's correlation coefficient increases by 112%, highlighting the effectiveness of ThermalWrist. We also investigate the limitation with respect to the ambient temperature where ThermalWrist works effectively. The result shows ThermalWrist works well in the normal office environment, which is 22.91 °C and above. [ABSTRACT FROM AUTHOR]