270 research outputs found
Road-to-Vehicle Communications with Time-Dependent Anonymity: A Light Weight Construction and its Experimental Results
This paper describes techniques that enable vehicles to collect local information (such as road conditions and traffic information) and report it via road-to-vehicle communications. To exclude malicious data, the collected information is signed by each vehicle. In this communications system, the location privacy of vehicles must be maintained. However, simultaneously linkable information (such as travel routes) is also important. That is, no such linkable information can be collected when full anonymity is guaranteed using cryptographic tools such as group signatures. Similarly, continuous linkability (via pseudonyms, for example) may also cause problem from the viewpoint of privacy.
In this paper, we propose a road-to-vehicle communication system with relaxed anonymity via group signatures with time-token dependent linking (GS-TDL). Briefly, a vehicle is unlinkable unless it generates multiple signatures in the same time period. We provide our experimental results (using the RELIC library on a cheap and constrained computational power device, Raspberry Pi), and simulate our system by using a traffic simulator (PTV), a radio wave propagation analysis tool (RapLab), and a network simulator (QualNet).
Though a similar functionality of time-token dependent linking was proposed by Wu, Domingo-Ferrer and Gonzälez-Nicoläs (IEEE T. Vehicular Technology 2010), we can show an attack against the scheme where anyone can forge a valid group signature without using a secret key. In contrast, our GS-TDL scheme is provably secure.
In addition to the time-dependent linking property, our GS-TDL scheme supports verifier-local revocation (VLR), where a signer (vehicle) is not involved in the revocation procedure. It is particularly worth noting that no secret key or certificate of a signer (vehicle) must be updated whereas the security credential management system (SCMS) must update certificates frequently for vehicle privacy. Moreover, our technique maintains constant signing and verification costs by using the linkable part of signatures. This might be of independent interest
A Revocable Group Signature Scheme with Scalability from Simple Assumptions and Its Application to Identity Management
Group signatures are signatures providing signer anonymity where signers can produce signatures on behalf of the group that they belong to. Although such anonymity is quite attractive considering privacy issues, it is not trivial to check whether a signer has been revoked or not. Thus, how to revoke the rights of signers is one of the major topics in the research on group signatures. In particular, scalability, where the signing and verification costs and the signature size are constant in terms of the number of signers N, and other costs regarding signers are at most logarithmic in N, is quite important.
In this paper, we propose a revocable group signature scheme which is currently more efficient compared to previous all scalable schemes. Moreover, our revocable group signature scheme is secure under simple assumptions (in the random oracle model), whereas all scalable schemes are secure under q-type assumptions. We implemented our scheme by employing Barreto-Lynn-Scott curves of embedding degree 12 over a 455-bit prime field (BLS-12-455), and Barreto-Naehrig curves of embedding degree 12 over a 382-bit prime field (BN-12-382), respectively, by using the RELIC library. We showed that the online running times of our signing algorithm were approximately 14 msec (BLS-12-455) and 11 msec (BN-12-382), and those of our verification algorithm were approximately 20 msec (BLS-12-455) and 16 msec (BN-12-382), respectively. Finally, we showed that our scheme is applied to an identity management system proposed by Isshiki et al
IRE1-XBP1 Pathway of the Unfolded Protein Response Is Required during Early Differentiation of C2C12 Myoblasts
ArticleInternational Journal of Molecular Sciences. 21(1): 182. (2019)journal articl
Intrapulmonary lymph nodes: thin-section CT findings, pathological findings, and CT differential diagnosis from pulmonary metastatic nodules.
We compared the thin-section CT findings of 11 intrapulmonary lymph nodes with pathological findings and evaluated the possibility of CT scan differential diagnosis from pulmonary metastatic nodules. First, we retrospectively reviewed CT scan and pathological findings of intrapulmonary lymph nodes. The median size of these nodules was 6.2 mm. The nodules appeared round (n=3) or angular (n=8) in shape with a sharp border, and they were found below the level of the carina. The median distance from the nearest pleural surface was 4.6 mm, and 3 of the 11 nodules were attached to the pleura. On thin-section CT scan, linear densities extending from the intrapulmonary lymph nodes were frequently visualized, and were pathologically proven to be ectatic lymphoid channels. We then compared the thin-section CT findings of 8 metastatic nodules less than 1 cm in diameter with those of the 11 intrapulmonary lymph nodes. The median size of these nodules was 6.8 mm, and the median distance from the nearest pleural surface was 16 mm. All nodules appeared round in shape. None of the nodules had linear densities extending from the nodules. The linear densities on thin-section CT scan may be the most useful characteristic of intrapulmonary lymph nodes, when differential diagnosis from metastatic nodules is necessary.</p
Tumor Shrinkage in Response to Vitamin K2 in Hepatocellular Carcinoma with Multiple Lung Metastases: A Case Report
Introduction: Advanced or metastatic hepatocellular carcinoma (HCC) can be lethal because of the limited therapeutic approach such as sorafenib. Recently, Vitamin K2 (VK2) has been increasingly recognized to have anti-cancer effects for HCC in vitro and vivo. However, the direct anti-cancer effect of VK2 to HCC has not been established yet in human.Presentation of Case: We presented here a 88-year-HCC patient displayed a tumor shrinkage in response to VK2 in multiple lung metastases, indicating the possibility of VK2 as an anti-cancer agent in human. Menatetrenone, a VK2 analogue, was introduced for multiple lung metastases as a palliative treatment, and thereafter multiple lung metastases, except one lung lesion, displayed tumor shrinkage and disappeared within five months after VK2 intake. The residual one lesion continued to grow up during the intake of VK2, suggesting that the residual tumor was insensitive to VK2 represented by tumor heterogeneity. Consequently, after a radiation therapy for the residual lesion, the elevated tumor markers of all were finally decreased into normal levels, and he is still alive for 18 months after VK2 intake without elevated tumor marker levels and toxic adverse effects.Conclusion:VK2 may be a therapeutic option for advanced and metastatic HCCs without any toxic adverse
Fabrication of a 64-Pixel TES Microcalorimeter Array with Iron Absorbers Uniquely Designed for 14.4-keV Solar Axion Search
If a hypothetical elementary particle called an axion exists, to solve the
strong CP problem, a 57Fe nucleus in the solar core could emit a 14.4-keV
monochromatic axion through the M1 transition. If such axions are once more
transformed into photons by a 57Fe absorber, a transition edge sensor (TES)
X-ray microcalorimeter should be able to detect them efficiently. We have
designed and fabricated a dedicated 64-pixel TES array with iron absorbers for
the solar axion search. In order to decrease the effect of iron magnetization
on spectroscopic performance, the iron absorber is placed next to the TES while
maintaining a certain distance. A gold thermal transfer strap connects them. We
have accomplished the electroplating of gold straps with high thermal
conductivity. The residual resistivity ratio (RRR) was over 23, more than eight
times higher than a previous evaporated strap. In addition, we successfully
electroplated pure-iron films of more than a few micrometers in thickness for
absorbers and a fabricated 64-pixel TES calorimeter structure.Comment: 5 pages, 5 figures, published in IEEE Transactions on Applied
Superconductivity on 8 March 202
Functional shoulder radiography with use of a dynamic flat panel detector
Our purpose in this study was to develop a functional form of radiography and to perform a quantitative analysis for the shoulder joint using a dynamic flat panel detector (FPD) system. We obtained dynamic images at a rate of 3.75 frames per second (fps) using an FPD system. Three patients and 5 healthy controls were studied with a clinically established frontal projection, with abduction of the arms. The arm angle, glenohumeral angle (G-angle), and scapulothoracic angle (S-angle) were measured on dynamic images. The ratio of the G-angle to the S-angle (GSR) was also evaluated quantitatively. In normal subjects, the G-angle and S-angle changed gradually along with the arm angle. The G-angle was approximately twice as large as the S-angle, resulting in a GSR of 2 throughout the abduction of the shoulder. Changes in G-angle and S-angle tended to be irregular in patients with shoulder disorders. The GSR of the thoracic outlet syndrome, recurrent dislocation of the shoulder joint, and anterior serratus muscle paralysis were 3-7.5, 4-9.5, and 3.5-7.5, respectively. The GSR of the anterior serratus muscle paralysis improved to approximately 2 after orthopedic treatment. Our preliminary results indicated that functional radiography by FPD and computer-aided quantitative analysis is useful for diagnosis of some shoulder disorders, such as the thoracic outlet syndrome, recurrent dislocation of the shoulder joint, and anterior serratus muscle paralysis. The technique and procedures described comprise a simple, functional shoulder radiographic method for evaluation of the therapeutic effects of surgery and/or rehabilitation. © 2014 The Author(s)
Delayed Giant Pseudoaneurysm With Left-to-Right Shunt Following Postinfarct Ventricular Septal Perforation Repair
Left ventricular pseudoaneurysm with a left-to-right shunt is extremely rare, requiring surgery if symptomatic; however, surgery has a high risk. Here, the case of a 77-year-old man with heart failure symptoms is reported, in which he develops a giant left ventricular pseudoaneurysm 16 months after ventricular septal perforation repair as a result of acute myocardial infarction, with mild shunt blood flow from the pseudoaneurysm to the right ventricle. Intraoperative findings showed a free wall rupture along the area where the patch was secured during the initial surgery. The patient was discharged on postoperative day 13, and postoperative examination revealed no abnormalities
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