Distributed H∞-Consensus Filtering for Attitude Tracking Using Ground-Based Radars.

This paper is concerned with the distributed H ∞ -consensus filtering problem on attitude tracking over a radar filter network subject to switching topology and random packet dropouts occurring in the data transmission from both the Sun sensor and the filters. Since ground-based radars cannot directly measure the satellite attitude, a Sun sensor is deployed at the satellite side and its measurements are transmitted to radar filters through different network communication channels while suffering from random packet dropouts with different probabilities. In the radar filter network, each radar filter receives data not only from the Sun sensor but also from its local neighboring radar filters in accordance with a switching network topology. A delicate distributed H ∞ -consensus filtering algorithm, which incorporates the effects of switching network topology and random packet dropouts, is adopted to estimate attitude and attitude-rate. The algorithm guarantees H ∞ -consensus attenuation performance for the estimation deviations among radar filters, and the robustness against the switching network topology and packet dropouts for the radar filter network. The illustrative examples are given to verify the effectiveness of the proposed distributed H ∞ -consensus filtering algorithm.

The value of the air bronchogram sign on CT image in the identification of different solitary pulmonary consolidation lesions.

The aim of the present study is to investigate the value of air bronchogram sign on computed tomography (CT) image in the differential diagnosis of solitary pulmonary consolidation lesions (SPLs).A total of 105 patients (including 39 cases of lung cancer, 43 cases of tuberculosis, and 23 cases of pneumonia) with SPLs were evaluated for the CT features of air bronchogram sign in this retrospective study. The shape and lumen of the bronchi with air bronchogram sign, the length of the involved bronchus with air bronchogram sign, the length of lesion on the same plane and direction, and the ratio between the length of the involved bronchus and that of the lesion were evaluated.In total, there were 172 segmental and subsegmental bronchi involved. There were 62 segmental and subsegmental bronchi involved among 39 lung cancer cases, 77 segmental and subsegmental bronchi involved among 43 tuberculosis cases, and 33 segmental and subsegmental bronchi involved among 23 pneumonia cases. The shape of the bronchi with air bronchogram sign was significantly different among lung cancer, tuberculosis, and pneumonia (P < .05). The lumen of the bronchi with air bronchogram sign was also significantly different among the 3 SPLs (P < .05). The length of the involved bronchus with air bronchogram sign and the ratio between the length of the involved bronchus and that of the lesion were significantly different between lung cancer and tuberculosis (P < .05), or between lung cancer and pneumonia (P < .05), but not between tuberculosis and pneumonia (P > .05). No significant difference was found in the length of lesion among the 3 SPLs (P > .05).The shape and lumen of the bronchi with air bronchogram sign can be used to distinguish lung cancer, tuberculosis, and pneumonia. The length of the involved bronchus with air bronchogram sign and the ratio between the length of the involved bronchus and that of the lesion can be used to distinguish lung cancer from tuberculosis and pneumonia.

[The advantage of delayed-phase multi-slice Computed Tomography for the diagnosis of intracranial tuberculosis].

OBJECTIVE: To study the advantages of delayed phase scan at 5 minutes using multi-slice Computed Tomography (CT) for the diagnosis of intracranial tuberculosis. METHODS: Conventional non-contrast and dual-phase contrast enhancement were performed using 16-slice spiral CT for brain scanning. Arterial phase was performed 25 seconds after the injection of contrast agent, and the delayed phase was performed at 5 minutes. Then the ability of two phase images in intracranial tuberculosis displaying was evaluated. RESULTS: A total of 526 lesions in 30 patients were found. Delayed phase scan was superior to arterial phase in the ability of displaying the thickening of meninges, either basal cistern, pia mater or ependymal (P<0.01). The demonstration of lesion size and margins of tuberculoma was also better in delayed phase scan (P<0.01). The delayed phase scan was significantly better in distinguishing lesions and adjacent vascular sections in the sulcus (P<0.01). CONCLUSION: The delayed phase scan has obvious advantages in the display of intracranial tuberculosis.

Multi-slice computed tomography 5-minute delayed scan is superior to immediate scan after contrast media application in characterization of intracranial tuberculosis.

BACKGROUND: The aim of this study was to determine whether the diagnosis of intracranial tuberculosis (TB) can be improved when multi-slice computed tomography (MSCT) scans are taken with a 5-min delay after contrast media application. MATERIAL AND METHODS: Pre- and post-contrast CT scans of the head were obtained from 30 patients using a 16-slice spiral CT. Dual-phase acquisition was performed immediately and 5 min after contrast agent injection. Diagnostic values of different images were compared using a scoring system applied by 2 experienced radiologists. RESULTS: We found 526 lesions in 30 patients, including 22 meningeal thickenings, 235 meningeal tuberculomas/tubercles, and 269 parenchymal tuberculomas/tubercles. Images obtained with 5-min delayed scan time were superior in terms of lesion size and meningeal thickening outlining in all disease types (P<0.01). The ability to distinguish between vascular sections from the cerebral sulcus and tubercle was also improved (P<0.01). CONCLUSIONS: Image acquisition with 5-min delay after contrast agent injection should be performed as a standard scanning protocol to diagnose intracranial TB.