Wang R.,Soochow University of China |
Wang R.,Lamar University |
Burleigh S.C.,Jet Propulsion Laboratory |
Parikh P.,Terarecon |
And 2 more authors.
IEEE/ACM Transactions on Networking | Year: 2011
Delay/disruption-tolerant networking (DTN) technology offers a new solution to highly stressed communications in space environments, especially those with long link delay and frequent link disruptions in deep-space missions. To date, little work has been done in evaluating the performance of the available "convergence layer" protocols of DTN, especially the Licklider Transmission Protocol (LTP), when they are applied to an interplanetary Internet (IPN). In this paper, we present an experimental evaluation of the Bundle Protocol (BP) running over various "convergence layer" protocols in a simulated cislunar communications environment characterized by varying degrees of signal propagation delay and data loss. We focus on the LTP convergence layer (LTPCL) adapter running on top of UDP/IP (i.e., BP/LTPCL/UDP/IP). The performance of BP/LTPCL/UDP/IP in realistic file transfers over a PC-based network test bed is compared to that of two other DTN protocol stack options, BP/TCPCL/TCP/IP and BP/UDPCL/UDP/IP. A statistical method of t-test is also used for analysis of the experimental results. The experiment results show that LTPCL has a significant performance advantage over Transmission Control Protocol convergence layer (TCPCL) for link delays longer than 4000 ms regardless of the bit error rate (BER). For a very lossy channel with a BER of around 10 -5, LTPCL has a significant goodput advantage over TCPCL at all the link delay levels studied, with an advantage of around 3000 B/s for delays longer than 1500 ms. LTPCL has a consistently significant goodput advantage over UDPCL, around 2500-3000 B/s, at all levels of link delays and BERs. © 2006 IEEE.
Zhan Y.-F.,General Hospital of Shenyang Military Command |
Feng X.,General Hospital of Shenyang Military Command |
Fu C.,Northeastern University China |
Bai G.-T.,Northeastern University China |
International Journal of Digital Content Technology and its Applications | Year: 2012
With the growing applications of digital images in medical health system and the development of computer networks, medical image encryption has become an important technology to protect patients' privacy when it is transmitted over open networks. Recently, chaos-based encryption approaches have been proven to be more effective for image encryption than other traditional methods (e.g. IDEA and AES). In this paper, we propose a novel chaos-based medical image cryptosystem with permutationdiffusion architecture, which provides efficient and secure transmissions for medical images over open networks. In the permutation stage, we introduce a novel shuffling method, which shuffles each pixel in plain image by exchanging it with a certain pixel selected by chaotic Logistic map. Compared with conventional permutation schemes based on Arnold cat map, Baker map and Standard map, the new scheme is superior in both key space and efficiency. In diffusion stage, each pixel is masked according to both key stream element and previous ciphered pixel so as to make the cryptosystem secure against differential attack. Intensive cryptanalysis is carried out and the experimental results demonstrate that the cryptosystem can withstand all kinds of known attacks, which includes brute-force attack, differential attack, known/chosen plain-text attack as well as various statistical attacks. Moreover, efficiency test indicates that the cryptosystem is efficient enough for real-time medical image protection applications.
Fu C.,Northeastern University China |
Meng W.-H.,Northern Hospital |
Zhan Y.-F.,Northern Hospital |
Zhu Z.-L.,Northeastern University China |
And 3 more authors.
Computers in Biology and Medicine | Year: 2013
Recently, the increasing demand for telemedicine services has raised interest in the use of medical image protection technology. Conventional block ciphers are poorly suited to image protection due to the size of image data and increasing demand for real-time teleradiology and other online telehealth applications. To meet this challenge, this paper presents a novel chaos-based medical image encryption scheme. To address the efficiency problem encountered by many existing permutation-substitution type image ciphers, the proposed scheme introduces a substitution mechanism in the permutation process through a bit-level shuffling algorithm. As the pixel value mixing effect is contributed by both the improved permutation process and the original substitution process, the same level of security can be achieved in a fewer number of overall rounds. The results indicate that the proposed approach provides an efficient method for real-time secure medical image transmission over public networks. © 2013 Elsevier Ltd.
Potential of right to left ventricular volume ratio measured on chest CT for the prediction of pulmonary hypertension: Correlation with pulmonary arterial systolic pressure estimated by echocardiography
Lee H.,Korea University |
Kim S.Y.,Seoul Medical Center |
Lee S.J.,Terarecon |
Kim J.K.,Chung - Ang University |
And 2 more authors.
European Radiology | Year: 2012
Objectives To investigate the correlation of right ventricular (RV) to left ventricular (LV) volume ratio measured by chest CT with pulmonary arterial systolic pressure (PASP) estimated by echocardiography. Methods 104 patients (72.47∓13.64 years; 39 male) who had undergone chest CT and echocardiography were divided into two groups (hypertensive and normotensive) based upon an echocardiography-derived PASP of 25 mmHg. RV to LV volume ratios (RVV/LVV) were calculated. RVV/ LVV was then correlated with PASP using regression analysis. The Area Under the Curve (AUC) for predicting pulmonary hypertension on chest CT was calculated. Results In the hypertensive group, the mean PASP was 46.29∓14.42 mmHg (29-98 mmHg) and there was strong correlation between the RVV/LVV and PASP (R00.82, P < 0.001). The intraobserver and interobserver correlation coefficients for RVV/LVV were 0.990 and 0.892. RVV/LVV was 1.01∓0.44 (0.51-2.77) in the hypertensive and 0.72∓0.14 (0.52-1.11) in the normotensive group (P <0.05). With 0.9 as the cutoff for RVV/LVV, sensitivity and specificity for predicting pulmonary hypertension over 40 mmHg were 79.5 % and 90 %, respectively. The AUC for predicting pulmonary hypertension was 0.87 Conclusion RV/LV volume ratios on chest CT correlate well with PASP estimated by echocardiography and can be used to predict pulmonary hypertension over 40 mmHg with high sensitivity and specificity. Key Points ̇ Chest CTis widely used in patients whomay have pulmonary hypertension. ̇ Cardiac ventricular volume ratios on chest CT correlate with pulmonary arterial systolic pressure. ̇ A R/L ventricular volume ratio >0.9 usually indicates pulmonary hypertension >40 mmHg. ̇ Information available on routine chest CT may help predict pulmonary hypertension. © European Society of Radiology 2012.
Terarecon | Date: 2014-11-04
According to one embodiment, at least a portion of medical information of a patient is displayed within MRCS executed within a local device, the medical information including medical treatment history of the patient. At least a portion of the displayed medical information of the patient is transmitted to a medical imaging processing server over a network, where the transmitted medical information includes a patient identifier (ID) of the patient. Both the at least a portion of patient medical information and one or more medical images are displayed within the MRCS, where the medical images are associated with the patient and rendered by the medical image processing server. A set of icons representing a set of image processing tools is displayed within the MRCS, which when activated by a user, allow an image to be manipulated by the imaging processing server.