Cloud storage services are widely used across the world. Cloud storage services can be virtualized, decentralized, they are also can be access by mobile phones. That is a great challenge to traditional digital forensics. In this paper, we focus on the most popular cloud storage services, and choose the iOS system as platform. Our experiments show what kinds of data remnants can be found. We also presented how the digital investigators to view the contents, even the original files cannot be recovered.

Dental radiography plays an important role in clinical diagnosis, treatment and surgery. In recent years, efforts have been made on developing computerized dental X-ray image analysis systems for clinical usages. A novel framework for objective evaluation of automatic dental radiography analysis algorithms has been established under the auspices of the IEEE International Symposium on Biomedical Imaging 2015 Bitewing Radiography Caries Detection Challenge and Cephalometric X-ray Image Analysis Challenge. In this article, we present the datasets, methods and results of the challenge and lay down the principles for future uses of this benchmark. The main contributions of the challenge include the creation of the dental anatomy data repository of bitewing radiographs, the creation of the anatomical abnormality classification data repository of cephalometric radiographs, and the definition of objective quantitative evaluation for comparison and ranking of the algorithms. With this benchmark, seven automatic methods for analysing cephalometric X-ray image and two automatic methods for detecting bitewing radiography caries have been compared, and detailed quantitative evaluation results are presented in this paper. Based on the quantitative evaluation results, we believe automatic dental radiography analysis is still a challenging and unsolved problem. The datasets and the evaluation software will be made available to the research community, further encouraging future developments in this field. (http://www-o.ntust.edu.tw/~cweiwang/ISBI2015/).

Cephalometric analysis is an essential clinical and research tool in orthodontics for the orthodontic analysis and treatment planning. This paper presents the evaluation of the methods submitted to the Automatic Cephalometric X-Ray Landmark Detection Challenge, held at the IEEE International Symposium on Biomedical Imaging 2014 with an on-site competition. The challenge was set to explore and compare automatic landmark detection methods in application to cephalometric X-ray images. Methods were evaluated on a common database including cephalograms of 300 patients aged six to 60 years, collected from the Dental Department, Tri-Service General Hospital, Taiwan, and manually marked anatomical landmarks as the ground truth data, generated by two experienced medical doctors. Quantitative evaluation was performed to compare the results of a representative selection of current methods submitted to the challenge. Experimental results show that three methods are able to achieve detection rates greater than 80% using the 4 mm precision range, but only one method achieves a detection rate greater than 70% using the 2 mm precision range, which is the acceptable precision range in clinical practice. The study provides insights into the performance of different landmark detection approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques.

Data hiding is a technique which embeds secret data into cover media. It is important to the multimedia security and has been widely studied. Recently, some researchers paid attention to reversible data hiding methods. These methods can reconstruct the original image from the stego-image when embedded data are extracted. In this paper, we propose a new reversible steganographic method for vector quantization (VQ) compressed images. The new method uses the hit pattern to achieve reversibility, and the hit pattern strategy successfully reduces the overhead. The codebook is partitioned by the extension method which makes the stego-image have good visual features. Also, a look-up table is used to speed up the partitioning operation. Compared to Chang et al.'s method, the experimental results show that the proposed method has higher capacity, better visual quality, and lower running time.