esa-sceva/satcom-chunk-collection huggingface dataset:
# An Access Control Model for Preventing Virtual Machine Hopping Attack
## 4 Methods
### PVMH Model Design
#### 4.1.3 State Transition Rules  
Based on BLP security criterion and Biba model, the PVMH model improves the integrity and confidentiality of the BLP model to a certain extent. The PVMH model includes 11 state transition rules, which are expressed as \(PVMH-R_{i}\), where \(1\ \leq i\leq 11\). The domain of the rule is denoted as \(dom(PVMH-R_{i})\). The output result is defined as the set \(D=\{yes,no,?\}\), where \"\(yes\)\" accepts the request, \"\(no\)\" rejects the request and \"?\" means the request is illegal, which does not belong to any request domain.  
**Rule 1 (\(PVMH-R_{1}\) (get-read)).** Subject virtual machine \(S_{i}\) accesses object virtual machine \(O_{j}\) in read-only (\(r\)) mode. The definition is \(dom(PVMH-R_{1})=\left\{R_{k}\ |\ \left(g,\ S_{i},\ O_{j},\ r\right)\in R ^{(1)}\right\}\). This pseudo code is as follow:  
\[PVMH-R_{1}\ (R_{k}\,\ v)=\left\{\begin{array}{ccc}(?,\ v)&if\ R_{k}\
otin dom( PVMH-R_{1})\\ (yes,(b\cup\ \{\left(S_{i},\ O_{j}\,\ r\right)\},M,f,H))&if\ [R_{k}\in dom( PVMH-R_{1})]\\ &\  
**Rule 3 (\(PVMH-R_{3}\) (get-write)).** Subject virtual machine \(S_{i}\) accesses object virtual machine \(O_{j}\) or \(S_{T}\) (trusted subject) accessed object virtual machine \(O_{j}\) in read-write (\(w\)) mode. The definition is \(dom(PVMH-R_{3})=\left\{R_{k}\ |\ \left(g,\ S_{i},\ O_{j},\ w\right)\in\ R^{(1)}\right\}\). This pseudo code is as follow:  
\[PVMH-R_{3}\left(R_{k}\,\ v\right)=  
access set \(b\) while notation \(OPE(S_{i})=\left(\{S\}\times O_{j}\times A\right)\cap b\) refers to all access from \(S_{i}\) to the deleted virtual machine in current access set \(b\).  
If the decision is \"_yes_\", \(O_{j}\) is deleted and, meanwhile, the related element is removed from current access \(b\), access matrix \(M\), and object level \(H\).  
**Rule 7 (\(PVMH-R_{7}\) (rescind-read/append/write)).** The Hypervisor (\(S_{\lambda}\)) needs to revoke permission for subject virtual machine \(S_{i}\) accessing object virtual machine \(O_{j}\), including read-only, write-only, or read-write. The definition is \(dom(PVMH-R_{7})=\left\{R_{k}\mid\left(S_{\lambda},r,\,S_{i},O_{j},x\right)\in R ^{(2)}\right\},\ x\ \in\ A\). The pseudo code is as follow:  
\[PVMH-R_{7}\left(R_{k}\,\ v\right)=\left\{\begin{array}{cl}\left(7,\ v \right)&if\ R_{k}\
otin dom(PVMH-R_{7})\\ \left(yes,\left(b-\left(S_{i},O_{j},x\right),M\backslash M_{ij}-\{x\},f,H \right)\right)&if\ \left[R_{k}\in dom(PVMH-R_{7})\right]\\ &\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \  
Notation \(f_{ht}\) refers to the highest writing-up level of the subject, while \"\(Highest\)\" refers to the highest writing-up level of the subject granted by administration. If the decision is \"yes\", the highest writing-up level of the subject is updated to \"\(Highest\)\".  
**Rule 10** (\(PVMH-R_{10}\) (\(modify\)-\(f_{oc}\))): _The trusted subject needs to modify the lowest writing-up level for a certain subject virtual machine. The definition is \(dom(PVMH-R_{10})=\left\{R_{k}\ |\ \left(
## 3 Problem Formulation and Proposed Model
### The Proposed Model: CPS Signal Acquisition  
From an operational perspective, the design and implementation of the CPS represent the most relevant concern of the proposed study, as they represent the connection between the physical world (the monitored machine/equipment) and the cyber world. As discussed in Section 2, [PERSON] et al. [23] proposed a unified 5C-level architecture as a guideline for the implementation of CPSs in Industry 4.0 manufacturing systems (smart connector level). In this sense, the signal acquisition is part of the CPS architecture itself. Regarding the behaviour and structure of the monitored machine/equipment, it is essential to choose carefully:  
* The typology and features of the sensors to be used (e.g., accuracy and response time);
* Their positioning within the system;
* A standardised communication protocol for data transfer, such as MTConnect [27].  
Figure 2: Self-detected condition-based maintenance framework.  
By analysing the history of the failures of a generic system together with its design features, it is possible to derive some recurrent problems and critical components. It is worth noting that the analyst may also adopt more sophisticated top-down approaches, such as Failure Modes, Effects and Criticality Analysis. (FMECA, MIL-P-1629, 1949), to decompose the system into its constituent elements in order to identify system's critical failures. The state of critical components must be monitored and analysed. Even if our approach can be applied to every machine/equipment, the initial definition, deployment, and setup of the CPS need to be conducted with the help of maintenance technicians. Their initial contribution, in fact, together with the design team's support, turn out to be crucial for a successful implementation at least at the current stage of development. However, in the coming years, the achievements of big data analysis and the availability of data from different kinds of machines will permit an automatic or \"supervised\" choice of the sensors themselves.
# IoT-Portrait: Automatically Identifying IoT Devices via Transformer with Incremental Learning
## 7 Conclusions  
In this paper, we design IoT-Portrait, an automatic IoT device identification framework based on a transformer. Compared with previous works, IoT-Portrait leverages an information acquisition scheme, combining both active and passive approaches to reduce the manual effort of labeling. In addition, IoT-Portrait uses a transformer neural network to mine potential features in the IoT device's traffic. For the problem of catastrophic forgetting, IoT-Portrait applies the class incremental learning method to retrain the model when new devices join the network. To the best of our knowledge, IoT-Portrait is the first work that applies the class incremental learning method to IoT device identification. The experimental results show that IoT-Portrait achieves high accuracy for IoT device identification and is well resistant to catastrophic forgetting.  
Our results show that IoT devices can be well identified through traffic information, and also verify the feasibility of class incremental learning in IoT device identification. We will perform more research to overcome the interference of network fluctuations on IoT device identification and attempt more class incremental learning methods in the future.  
Conceptualization, [PERSON] and J.L.; methodology, [PERSON] and J.L.; software, [PERSON] and J.L.; validation, [PERSON]; formal analysis, [PERSON]; investigation, [PERSON] and J.L.; resources, [PERSON]; data curation, [PERSON]; writing--original draft preparation, [PERSON]; writing--review and editing, [PERSON]; visualization, [PERSON]; supervision, [PERSON]; project administration, [PERSON]; funding acquisition, [PERSON] All authors have read and agreed to the published version of the manuscript.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Name** & **Method** & **Label** & **Prediction Accuracy** &
\begin{tabular}{c} **Class Incremental** \\ **Learning Method** \\ \end{tabular} \\ \hline IoT-Sentinel [6] & Random Forest & manually & 82\% & no \\ PAB [8] & KNN & manually & 93\% & no \\ HomeMole [15] & BLSTM & manually & 99\% & no \\ IoT-Portrait & Transformer & automatically & 99\% & yes \\ \hline \hline \end{tabular}
\end{table}
Table 4: The comparison of IoT-Portrait and other related works.  
**Funding:** This work is sponsored by the National Natural Science Foundation of China granted No.61872430, 61402342, 61772384, the National Basic Research Program of China 973 Program granted No.2014 CB340601, the Foundation of Science and Technology on Information Assurance Laboratory (No. KJ-17-103), and the Hubei Province Key Research and Development Program under Grants 2020 BAA003, 2021 BAA027.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors express great appreciation to [PERSON], [PERSON], and [PERSON].  
**Conflicts of Interest:** The authors declare no conflicts of interest.
# Fast Path Generation Algorithm for Mobile Robot Navigation Using Hybrid Map
## 2 Related Works  
This paper examines the environment map and path generation algorithm used by mobile robots for path planning. Existing path generation algorithms primarily focus on creating paths that minimize travel time and distance from a specific location to the destination.
## 2 System Topology
### Topology of the Proposed Novel PET  
The proposed novel PET consists of three parts, namely the input stage, the isolation stage, and the output stage. The topology is shown in Figure 2. The input stage connects with the medium- and high-voltage AC distribution network by MMC, and the sub-modules (SMs) of MMC are connected in series to make PET suitable for higher voltage levels. MMC uses relatively fewer filters while retaining considerably high overall operational efficiency and power quality, and lowering the requirement of withstand voltage of power semiconductor devices. Furthermore, the input stage can achieve unity power factor or constant power factor operation through effective regulating.  
The isolation stage applies the dual-active-bridge (DAB) bidirectional DC/DC converters as the core component to enable up/down voltage conversion and electrical isolation among different ports. In comparison to the other DC/DC converters, DAB has high power transfer capability, and has  
Figure 1: System topology of the developed three-phase power electronic transformer (PET) for medium- and high-voltage distribution network.  
the advantages of a modularized symmetrical structure, bidirectional power flow capability, rapid dynamic response, and easy implementation of soft switching. As shown in Figure 2, the isolation stage consists of two parts where some DAB modules connect with the AC port at the output stage via ISOS, others connect to the DC port at the output stage via ISOP. The isolation stage of existing PET only adopts the ISOP connection, while the proposed combined connection of ISOS and ISOP enables the output stage to meet the access requirements of AC/DC power grids with significantly different voltage levels more easily.  
The output stage includes two output ports, namely the AC output port and the DC output port. Different structures can be applied for the port converter according to the voltage level of the connected network and the power transmission mode, etc. In the model established in this paper, the AC output port connects to the 10 kV AC distribution network and the MMC structure is utilized. In addition, a three-phase two-level inverter structure can be adopted when the AC output port connects to the low-voltage grid. The DC output port connects the low-voltage DC distribution network through a buck/boost-type DC/DC converter. The study conducted in this paper focuses on the PET with two output ports at the output stage, while it is worth mentioning that the amount of AC/DC output ports can be increased as needed.
# Evolution and Testing of NB-IoT Solutions
## 5 End-to-End NB-IoT Testing  
This section describes the new IoT scenarios specified in the TRIANGLE testbed for testing of NB-IoT solutions and demonstrates its potential explaining initial results. The purpose of this section is to demonstrate the potential offered by the TRIANGLE testbed to reproduce realistic NB-IoT network configurations, execute tests, collect measurements, and analyze the performance of the solution under testing.
# An Approach of Path Optimization Algorithm for 3D Concrete Printing Based on Graph Theory
## 4 Discussion  
Changing the running speed of the nozzle can also affect the printing time, but we did not do that. The reason is that the running speed of the nozzle can only be changed in a small range during the actual printing process; otherwise, a fracture surface will be generated inside the 3D concrete components. The consequence of this result is extremely serious and will change the interfacial force transmission path of the components. At the same time, the volume and shape of the final 3D concrete component are fixed no matter what method is used to print. This means that the required material and the path that the nozzle must run are the same during the printing process. Therefore, we focused our attention on shortening the unnecessary path of the nozzle run, also known as reducing the idle strokes; this will not change the shape and volume of the concrete components, but it can shorten the printing time.  
The flowability of the material is an important factor that affects the forming quality of the concrete components. The means of influence is that when the nozzle needs to stop feeding, the concrete component will cause local accumulation or local surface fracture due to the fluidity of the material. For this problem, we choose to reduce the number of the nozzle needs to stop feeding (reduce the head-up times of the nozzle) to solve it. The benefit is obvious because no matter how strong or weak the material flowability is, the impact on the forming quality of concrete components during the continuous printing process is always relatively small. Reducing the number of nozzle head-ups ensures the continuity of the printing process. Of course, in actual printing, there are many factors that can affect the forming quality of concrete components; what we do is maximize the forming quality by changing the running path of the nozzle.  
In the 3D concrete printing process, the formation of a complete concrete component requires the accumulation of materials layer by layer. This means that the time reduction  
Figure 10: Concrete component printed by offset contour scanning algorithm.  
Figure 9: Concrete component printed by the method in this paper.  
and the local accumulation reduction of each layer will eventually accumulate when printing, and these reductions can be considered when printing large-scale components. In fact, many large concrete components cannot be printed due to the long printing time and large local accumulation. The method in this paper can provide a feasible printing path.
# Ephemeral Node Identifiers for Enhanced Flow Privacy
## 5 Discussion
### Deployment and Scalability of eNIDs  
Deployment of the eNID mechanism is performed by updating a node's OS image to include the modifications for ILNP with eNIDs. As evidenced by our implementation [17], it is possible to modify existing protocol code for an existing OS. This would then be deployed using automated remote (aka \"over-the-air\") updates that are now common for software systems including OS distributions.  
The use of eNIDs modifies the IPv6 packet format only, and does not introduce any new control protocol messages, or require new network entities, such as proxies or gateways. So, the eNID mechanism can also be deployed incrementally, only by the nodes that need it, and used without requiring any network upgrades. For the tests and experiments described in Sections 3.3.1 and 3.3.2, standard, commercial equipments was used, and no special configuration was required for the network components. ILNP packets using eNID values have a wire-image that is seen as an IPv6 packet.  
In terms of scalability, similar arguments apply. The ILNP-enabled/eNID-enabled OS images need only be deployed by those nodes that need to use them--a complete upgrade to all netwokr nodes is not needed. Again, for the tests and experiments described in Sections 3.3.1 and 3.3.2, there was no impact in terms of overhead on the other nodes or network components in those networks. As discussed above in Section 5.2, use of eNIDs at scale is likely to reduce local NDP traffic compared to TA-SLAAC. As the eNID generation and management is purely local to the client node (the initiator of the communication), there is no additional administrative overhead in deployment or operation.  
Server systems do not need to be aware that eNID mechanisms are in use by clients. Although our focus has been on privacy for client nodes, we discuss below the use of eNIDs at the server-side (Section 5.6).
## 3 Research Methodology
### Adaptive Mixing Ratio-\(\beta\)  
In the local model-training process of each client in the federated learning process, it is necessary to update the \(\beta\) value through gradient descent to obtain a suitable mixing ratio. In general image recognition learning, the loss value \(L\) can be expressed using Equation (6), where \(M\) is the neural network model, \(I\) is the input data, \(D_{label}\) is the labeled data, and \(f_{loss}\) is the cross-entropy loss function.  
\[L=f_{loss}\ (M(I),\ D_{label}) \tag{6}\]  
After calculating the loss between the prediction results and the true label data using Equation (6), the neural network model must update its parameters based on the loss through gradient descent to reduce the gap. The loss value of each client can be extended based on the loss function of the general image recognition learning task, as shown in Equation (7), where \(F_{g}\) is the global feature extraction term, \(F_{i}^{i}\) is the local feature extraction term of the i-th client, and \(G_{i}^{i}\) is the gradient descent of the i-th client.  
\[L_{i}=f_{loss}\ \Big{(}\Big{(}(1-\beta_{i})*F_{g}+\beta_{i}*F_{i}^{i}\Big{)} \circ G_{i}^{i}(I),\ D_{label}\Big{)} \tag{7}\]  
In Equation (7), each client has its own loss value due to different model parameters, so each client can update the \(\beta_{i}\) value according to the corresponding loss through gradient descent. And the model feature extraction term will be calculated with the (1-\(\beta_{i}\)) global model parameters and the \(\beta_{i}\) client model parameters of the previous round. In addition to updating the \(\beta_{i}\) value through gradient descent to adjust the mixing ratio, the initial \(\beta\) value will also impact the client's accuracy in that round. The results of personalized federated learning using various initial \(\beta\) values of 0.3, 0.5, and 0.7 are presented in Figure 2. According to the training results, when the initial value of \(\beta\) is closer to 1, such as 0.7, the training results are better than the other two values, which is consistent with Equation (6).
# Influence of Joint Stiffness and Motion Time on the Trajectories of Underactuated Robots
## 7 Conclusions  
This paper presents a study of a planar 3-DOF differentially flat underactuated robot, in which the last joint is equipped with a torsional spring in parallel with a torsional damper that accounts for friction losses. A specific mathematical model for the calculation of motor torques that exploits differential flatness properties in the Laplace domain was developed. Parametric calculations were performed to investigate the effects of the torsional spring stiffness and motion time on robot trajectories. The possibility of achieving the same trajectory by varying either parameter was highlighted. Additionally, experimental tests were carried out on a subsystem of the robot, and corroborated numerical results.  
The advantages of utilizing a partially actuated system, as opposed to a fully actuated one, were demonstrated, including the use of fewer motors and the resulting reduction in the area swept by the links to perform the task. Large reductions in the swept area can be achieved both by decreasing the stiffness of the nonactuated joint and shortening the motion time, but these solutions lead to an increase in motor torques (especially \(\tau_{2}\)), which have to be carefully evaluated in terms of energy consumption and motor encumbrance. These findings suggest that underactuated robotic systems have many potentialities and could be used in many applications, ranging from industrial automation to medical robotics and to walking robots.  
Further research will focus on the development of more complex underactuated systems (e.g., with a complex link geometry or with more DOFs) and on the application of these concepts in real-world scenarios. One interesting scenario is represented by planar robots operating in the vertical plane, where the nonlinear gravitational term is present, but the diffeomorphism can be defined [25]. Another interesting scenario is the planning of point-to-point motions with via points, which are useful to avoid collisions with obstacles.  
Conceptualization, M.T., A.D., M.B. and G.R.; methodology, M.T., A.D., M.B. and G.R.; software, M.T. and M.B.; validation, M.T. and A.D.; formal analysis, M.T., A.D., M.B. and G.R.; investigation, M.T., M.B. and G.R.; writing--original draft preparation, M.T. and M.B.; writing--review and editing, A.D. and G.R.; supervision, A.D. and G.R. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.
## 6 Industrial Applications of Lipase-Catalyzed Biodiesel  
Even though transesterification through alkaline catalysis is the preferred process in the majority of industrial biodiesel production plants [23], a few lipase-based processes have already been implemented to plant-scale operation. The collaboration of Novozymes (Bagsvaerd, Denmark) with Piedmont Biofuels (Pittsboro, NC, USA) resulted in a patent application to produce fatty acid alkyl esters, by a lipolytic enzyme in a solution containing triacylglycerol, alcohol, water, and glycerol [93, 127]. Viesel Fuel (Terrac Stuart, FL, USA) upgraded in 2013 its facility through an enzymatic process developed by Novozymes (Denmark) to use brown grease and waste cooking oil to produce up to 11 million gallons biodiesel per year using Eversa Transform(r) lipase from Novozymes, a soluble lipase produced by a genetically modified strain of _Aspergillus oryzae_[128], and an ion exchange resin system for removal of remaining free fatty acids during crude biodiesel refining [129, 130]. Viesel Fuel, Novozymes and Tactical Fabrication also collaborated with Buster Biofuels to upgrade its facility in San Diego (CA, USA) to produce up to 5 million gallons per year [131]. Lvming and Environmental Protection Technology Co. Ltd. (Shanghai, China) used lipase of _Candida_ sp. to produce 10,000 tons per year from waste frying oil [95]. A plant in Sumare (Sao Paulo, Brazil) produces biodiesel from mixed beef tallow and soybean oil using Callera(r) Trans L lipase in a batch reactor [132]. These companies are using liquid lipase formulations but the efficiency of the process can be improved further by using recent developments in immobilized lipases. So, Hunan Rivers Bioengineering Co. Ltd. (Hunan, China) was reported to use Novozym 435(r) lipase in a stirred tank reactor to produce 20,000 tons of biodiesel per year. The enzyme is a lipase B from _Candida antarctica_ immobilized on a resin consisting of macroporous support formed by poly(methyl methacrylate) crosslinked with divinylbenzene [133]. New technology protected with patents [134] has been provided by EnzymoCore, a leading global producer company founded in 2007 in Israel and with several active biodiesel plants around the world. This company has developed modified-immobilized enzymes, supported on solid organic resins, with high resistance to methanol and able to produce biodiesel from any type of oil or fat, even those cheap and with very large content of free fatty acids and polar lipids [135].