Building identification refers to the recognition of the identity of a building when the building is sighted. With proper identification, additional useful information can be gained, such as the geographical information of the building and facility information within the building based on the recognized identity. However, existing studies related to building identification require additional information such as building images in advance, or have constraints on the types of possible input images. Therefore, we propose an approach that undertakes building identification using a building boundary map and smartphone sensors. Our approach measures the position of the user and the orientation of the user's view using sensors embedded in a smartphone. We find the building sighted by the user by reducing the area of buildings that can exist in the user's orientation in a step-by-step manner. During the validation of our approach, it identified the buildings with accuracy of up to 83.3% despite the inaccuracy of the building boundary map used and the error inherent in the user's position and orientation based on the smartphone.

Selective video encryption schemes for battery-powered video devices have been proposed to prevent illegal acquisition of recorded video during transmission. However, the transmission security of conventional schemes is lower than the fully encrypted transmission schemes because a substantial part of the recorded video remains unencrypted including significant metadata for decoding recorded video. In order to address this limitation, we propose a secure video transmission framework that selectively encrypts video metadata and frames on a per packet basis with a consideration of currently available computing power and transmission distance. Evaluation on a testbed demonstrates that the proposed framework provides enhanced video transmission security with less than half of the battery power consumption required by the fully encrypted transmission scheme.

Pairwise testing is an effective combinatorial test case generation approach in which test cases are developed to execute all possible pairwise combinations of system inputs. It can help reduce the number of test cases and save testing time yet still effective in finding defects. However, it is very difficult for practitioners to effectively apply pairwise testing in the real world because of the lack of suitable techniques and guidelines. To redress this situation, this paper conducts a case study of applying pairwise testing to system data derived from real-valued variable inputs. In order to apply pairwise testing to this case study, this paper develops a test procedure and a novel partitioning method to test derived data as a naïve application of the conventional pairwise testing that would produce a huge number of test cases. A comparative evaluation shows that the pairwise testing of the proposed approach is more effective than the random testing with a 12–20% higher fault detection ratio. Based on our experience, guidelines for applying pairwise testing in practice are also presented. Copyright © 2014 John Wiley & Sons, Ltd.

This paper proposes a novel cross-layer packet prioritization scheme that overcomes the limitations of conventional video prioritization schemes for IPTV system. In the conventional schemes, the Extend profile or frame unit is used for prioritization and these incur limited uses of the video prioritization schemes or unreliable transmission of the P-frame and B-frame headers. In order to overcome these limitations, the proposed scheme uses the MPEG-2 system information and the H.264/AVC NAL header information to prioritize the important video packets including the P-frame and B-frame headers. The experimental results using a testbed demonstrated that the proposed scheme has a significant performance enhancement over the conventional video prioritization schemes in terms of packet utilization ratio for video streaming, direct frame loss ratio, and PSNR.

Although 3D video has become popular, streaming over wireless network faces a number of challenges. Due to frequent frame losses in wireless networks, temporal asynchrony occurs and results in serious visual fatigue for viewers. In order to provide better quality of 3D video, this paper proposes a new scheme called the Temporal Synchronization Scheme (TSS) for live 3D video streaming over wireless networks. TSS delivers video frames for the left and right views in the same frame order with the same transmission priority and compensates for frame damage and loss during the decoding phase. In addition, a new metric called the Stereoscopic Temporal Variation Index (STVI) is proposed to measure the degree of temporal asynchrony in 3D video. Subjective assessments demonstrate that STVI is an objective metric for measuring subjective quality. Moreover, our study shows that the proposed scheme results in better 3D video quality than the conventional method in terms of STVI and MOS.

Variable length messages have been in use for a long time for efficient delivery of information. As there are many different ways, with varying complexity, to utilize message length variability, it is crucial to thoroughly test the capability of the parsers of such messages to ensure that they correctly handle the variability. However, testing techniques for message length variability were developed only in fragments in the past and therefore test developers who are faced with the task of testing variable length messages are left with little guidance or few techniques for handling them systematically. This paper develops an approach for systematic test cases generation for testing the parsers of variable length messages. To do so, we develop taxonomy of message length variabilities, and derive test requirement patterns for them using the taxonomy. Then test requirements for particular protocols can be derived from the patterns. A case study is conducted to show that the proposed taxonomy and the test requirement patterns are effective in deriving test cases for actual protocols. The results showed significant improvement over the conventional approach. It revealed many missed requirements that were not identified with the test requirements developed using the conventional intuition-based approach.