| 5351. |
- Karresand, Martin, et al.
(författare)
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Creating a Map of User Data in NTFS to Improve File Carving
- 2019
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Ingår i: Advances in Digital Forensics XV. - Cham : Springer. - 9783030287528 - 9783030287511 ; , s. 133-158
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Konferensbidrag (refereegranskat)abstract
- Digital forensics, and espesially, file carving are burdened by the large amounts of data that need to be processed. Attempts to solve this problem include efficient carving algorithms, parallel processing in the cloud and data reduction by filtering uninteresting files. This research addresses the problem by searching for data wher it is more likely to be found. This is accomplished by creating a probability map for finding unique data at various logical block addressing positions in storage media. SHA-1 hashes of 512B sectors are used to represent the data. The results, which are based on a collection of 30 NTFS partitions from computers runnign Microsoft Windows 7 and later versions, reveal that the mean probability of finding unique hash values at different logical block addressing positions vary between 12% and 41% in an NTFS partition. The probability map can be used by forensic analyst to prioritize relevant areas in storage media without the need for a working filesystem. It can also be used to increase the efficienty of hash-based carving by dinamically changing the random sampling frequency. The approach contributes to digital forensic processes by enabling them to focus on interesting regions in storage media, increasing the probability of obtaining relevant results faster. © IFIP International Federation for Information Processing 2019
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| 5352. |
- Karresand, M., et al.
(författare)
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Disk Cluster Allocation Behavior in Windows and NTFS
- 2020
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Ingår i: Mobile Networks and Applications. - : Springer. - 1383-469X .- 1572-8153. ; 5:1, s. 248-258
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Tidskriftsartikel (refereegranskat)abstract
- The allocation algorithm of a file system has a huge impact on almost all aspects of digital forensics, because it determines where data is placed on storage media. Yet there is only basic information available on the allocation algorithm of the currently most widely spread file system; NTFS. We have therefore studied the NTFS allocation algorithm and its behavior empirically. To do that we used two virtual machines running Windows 7 and 10 on NTFS formatted fixed size virtual hard disks, the first being 64 GiB and the latter 1 TiB in size. Files of different sizes were written to disk using two writing strategies and the $Bitmap files were manipulated to emulate file system fragmentation. Our results show that files written as one large block are allocated areas of decreasing size when the files are fragmented. The decrease in size is seen not only within files, but also between them. Hence a file having smaller fragments than another file is written after the file having larger fragments. We also found that a file written as a stream gets the opposite allocation behavior, i. e. its fragments are increasing in size as the file is written. The first allocated unit of a stream written file is always very small and hence easy to identify. The results of the experiment are of importance to the digital forensics field and will help improve the efficiency of for example file carving and timestamp verification. © 2019, The Author(s).
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| 5353. |
- Karresand, Martin, et al.
(författare)
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Using NTFS Cluster Allocation Behavior to Find the Location of User Data
- 2019
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Ingår i: Digital Investigation. The International Journal of Digital Forensics and Incident Response. - Oxon : Elsevier. - 1742-2876 .- 1873-202X. ; 29:Supplement, s. S51-S60
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Tidskriftsartikel (refereegranskat)abstract
- Digital forensics is heavily affected by the large and increasing amount of data to be processed. To solve the problem there is ongoing research to find more efficient carving algorithms, use parallel processing in the cloud, and reduce the amount of data by filtering uninteresting files. Our approach builds on the principle of searching where it is more probable to find what you are looking for. We therefore have empirically studied the behavior of the cluster allocation algorithm(s) in the New Technology File System (NTFS) to see where new data is actually placed on disk. The experiment consisted of randomly writing, increasing, reducing and deleting files in 32 newly installed Windows 7, 8, 8.1 and 10 virtual computers using VirtualBox. The result show that data are (as expected) more frequently allocated closer to the middle of the disk. Hence that area should be getting higher attention during a digital forensic investigation of a NTFS formatted hard disk. Knowledge of the probable position of user data can be used by a forensic investigator to prioritize relevant areas in storage media, without the need for a working file system. It can also be used to increase the efficiency of hash-based carving by dynamically changing the sampling frequency. Our findings also contributes to the digital forensics processes in general, which can now be focused on the interesting regions on storage devices, increasing the probability of getting relevant results faster. © 2019 Martin Karresand, Stefan Axelsson, Geir Olav Dyrkolbotn
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| 5354. |
- Karthik, K. R. G., et al.
(författare)
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Physical and Electrical Properties of Single Zn2SnO4 Nanowires
- 2011
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Ingår i: Electrochemical and solid-state letters. - Pennington, NJ : Electrochemical Society. - 1099-0062 .- 1944-8775. ; 14:1, s. K5-K7
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Tidskriftsartikel (refereegranskat)abstract
- Electrical characterizations of single Zn2SnO4 (ZTO) nanowire devices are presented. These include resistivity, mobility, and photosensing measurements. The resistivity and the mobility of the Zn2SnO4 nanowire were measured to be 5.6 cm and 0.2 cm2/Vs, respectively. These values were found to be strongly dependent on the amount of electron-donating defects and less dependent on the thickness of the nanowires. An increase in the resistivity when changing the ambient atmosphere is observed. This change is caused by defect states lying in the bandgap, as shown by photoluminescence. The results imply the potential of ZTO nanowires as phototransistors and other photosensitive devices. © 2010 The Electrochemical Society.
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| 5355. |
- Karumanchi, Sisir, et al.
(författare)
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Reactive control in environments with hard and soft hazards
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - Piscataway, N.J. : IEEE Press. - 9781467317375 ; , s. 2863-2868
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a generalization of reactive obstacle avoidance algorithms for mobile robots operating among soft hazards such as off-road slopes and deformable terrain. A new hazard avoidance scheme generalizes constraint based reactive algorithms [1], [2] from hard to soft hazards. Reactive controllers operate by directly parameterizing the closedloop dynamics of the system with respect to the environment the robot is operating in. Traditionally, reactive controllers are parameterized by weighting virtual attraction and repulsion forces from goals and obstacles [3], [4]. One pitfall of such parameterizations is sensitivity of the tuning parameters to the operating environment. A reactive controller tuned in one set of conditions is not applicable in another (e.g. a different density of obstacles). The algorithm presented in this paper has two key properties which are significant i) Parameterization is environment independent. ii) It can deal with non-binary environments that contain soft hazards. © 2012 IEEE.
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| 5356. |
- Kasiuliene, Alfreda, et al.
(författare)
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Accumulation of heavy metals in forest dwarf shrubs and dominant mosses as bioindicators of atmospheric pollution
- 2019
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Ingår i: Journal of Elementology. - Olsztyn : Polish Society for Magnesium Research. - 1644-2296. ; 24:3, s. 1079-1090
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Tidskriftsartikel (refereegranskat)abstract
- This article discusses the environmental concerns about heavy metal accumulation in dominant forest mosses and dwarf shrubs. Samples of two different species of mosses, such as glittering wood moss (Hylocomium splendens) and feathermoss (Pleurozium schreberi), and two species of dwarf shrubs, that is European blueberry (Vaccinium myrtillus) and lingonberry (Vaccinium vitis-idaea), were collected from specifically chosen areas with evident anthropogenic pollution (vicinity of an airport and close to heavy road traffic) and from contamination-free, secluded forest areas in Lithuania and Sweden. Instrumental analysis of heavy metals, including cadmium, chromium, copper, lead and zinc, revealed that the selected plant species tend to accumulate zinc and copper the most and chromium the least. Forest mosses, used as indicators of airborne pollution, accumulated less heavy metals than dwarf shrubs, indicating more metal accumulation from the soil. The results also revealed that forest, dwarf shrub leaves even picked from areas with known anthropogenic pollution sources were safe to use. since concentrations of cadmium and lead remained below the maximum permissible level. A multivariate data analysis model with two principle components explained more than 70% of the data variation. The heavy metal content in soil was the most distinctive factor separating the Lithuanian and Swedish sites. Cadmium and chromium soil contents were more significant in the Lithuanian soils, whereas copper, lead, and zinc were more significant in the Swedish soils.
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| 5357. |
- Kaur, Kuljeet, et al.
(författare)
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A Novel Resource Reservation Scheme for Mobile PHEVs in V2G Environment using Game Theoretical Approach
- 2015
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Ingår i: IEEE Transactions on Vehicular Technology. - Piscataway, NJ : IEEE Press. - 0018-9545 .- 1939-9359. ; 64:12, s. 5653-5666
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Tidskriftsartikel (refereegranskat)abstract
- With the widespread penetration of plug-in hybrid electric vehicles (PHEVs), the overall demand on micro-grids (MGs) may increase manifold in the near future. Unregulated power demands from PHEVs may increase the demand-supply gap at MG. Thus, in order to keep MGs stabilize, and cater the ever growing energy demands, there is a requirement of an intelligent solution to regulate, and manage PHEVs in vehicle-togrid (V2G) environment. Keeping in view the above issues, this paper proposes a novel scheme which aims to regulate PHEVs? charging, and discharging activities based on MGs? day-ahead load curves. These load curves are obtained by utilizing the existing load forecasting techniques such as-fuzzy logic (FL), and artificial neural networks (ANN). Efficient utilization of PHEVs according to these curves may play a vital role in flattening MG?s load profile. Thus, the proposed scheme works by reserving resources such as-time slots, and charging points for PHEVs during peak shaving, and valley filling. Different algorithms pertaining to resource reservation for PHEVs have also been designed. These algorithms employ the concepts of game theory, and 0/1 knapsack problem for supporting peak shaving, and valley filling respectively. Moreover, PHEVs are also utilized when there are transitions from valley filling to peak shaving areas in the load curves, and vice-versa. PHEVs involved in this process have both charging, and discharging capabilities, and are referred as dual-mode PHEVs. The proposed scheme has been tested with respect to various parameters, and its performance was found satisfactory. © 2015 IEEE
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| 5358. |
- Kazemi, Zahra, et al.
(författare)
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An Offline Hardware Security Assessment Approach using Symbol Assertion and Code Shredding
- 2022
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Ingår i: Proceedings of the Twenty Third International Symposium on Quality Electronic Design. - : IEEE. - 9781665494663 - 9781665494656 - 9781665494670
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Konferensbidrag (refereegranskat)abstract
- This paper presents an evaluation approach to analyze and prioritize the embedded software vulnerabilities against FIAs by using symbolic execution. The proposed approach is based on the code review analysis and highlights the potential software weakness points. It uses LLVM and its add-on named KLEE tool, which applies the symbolic assertion into the code under review. These tools are employed to obtain a vulnerability factor that is used to spot the corner cases in the execution paths of the code blocks. A case study has shown the effectiveness of the generated assertions in pinpointing the actual vulnerabilities. © 2022 IEEE.
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| 5359. |
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| 5360. |
- Keel, George, et al.
(författare)
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Time-driven activity-based costing for patients with multiple chronic conditions : a mixed-method study to cost care in a multidisciplinary and integrated care delivery centre at a university-affiliated tertiary teaching hospital in Stockholm, Sweden
- 2020
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Ingår i: BMJ Open. - London : BMJ Publishing Group Ltd. - 2044-6055. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study can be applied to cost the complex non-standardised processes used to treat patients with multiple chronic conditions. DESIGN: A mixed-method approach to cost analysis, following a modified healthcare-specific version of the seven-step Time-Driven Activity-Based Costing (TDABC) approach. SETTING: A multidisciplinary integrated and person-centred care delivery centre at a university-affiliated tertiary teaching hospital in Stockholm, Sweden, designed to improve care coordination for patients with multiple chronic conditions, specifically diabetes, cardiovascular disease and kidney disease. PARTICIPANTS: 314 patients (248 men and 66 women) fit inclusion criteria. Average age was 80 years. RESULTS: This modified TDABC analysis costed outpatient care for patients with multiple chronic conditions. The approach accounted for the difficulty of conceptualising care cycles. The estimated total cost, stratified by resources, can be reviewed together with existing managerial accounting statements to inform management decisions regarding the multidisciplinary centre. CONCLUSIONS: This article demonstrates that the healthcare-specific seven-step approach to TDABC can be applied to cost care for patients with multiple chronic conditions, where pathways are not yet discernable. It became clear that there was a need for slight methodological adaptations for this particular patient group to make it possible to cost these pathways, stratified by activity and resource. The value of this approach can be discerned from the way management incorporated the results of this analysis into the development of their hospital strategy. In the absence of integrated data infrastructures that can link patients and resources across financial, clinical and process data sets, the scalability of this method will be difficult. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.
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