A forward-secure e-mail protocol without certificated public keys

Forward secrecy in an e-mail system means that compromising of the long-term secret keys of the mail users and mail servers does not affect the confidentiality of the e-mail messages. Previous forward-secure e-mail protocols used the certified public keys of the users using PKI (Public Key Infrastructure). In this paper, we propose a password-based authenticated e-mail protocol providing forward secrecy. The proposed protocol does not require certified public keys and is sufficiently efficient to be executed on resource-restricted mobile devices.     

A modified advancing layers mesh generation for thin three-dimensional objects with variable thickness

A method of generating modified advancing layers mesh is proposed. In this paper the mesh generation process of semi-unstructured prismatic/tetrahedral mesh is presented for relatively thin three-dimensional geometries with variable thickness, as in the case of injection molding analysis. Prismatic meshes are generated by offsetting initial surface triangular meshes. During the mesh generation process, mesh quality is efficiently improved with the use of a new node relocation method. Finally, tetrahedral meshes are automatically generated in the rest of the domain. The mesh generating capability of the proposed algorithm is demonstrated with the several practical test cases.     

A remote user authentication scheme without using smart cards

User authentication is one of the fundamental procedures to ensure secure communications over an insecure public network channel. Especially, due to tamper-resistance and convenience in managing a password file, various user authentication schemes using smart cards have been proposed. A smart card however far from ubiquitous because of the high cost of a smart card and the infrastructure requirements. In this paper, we study secure user authentication using only a common storage device such as a universal serial bus (USB) memory, instead of using smart cards. We first show that the existing schemes using smart cards cannot be immediately converted into schemes using a common storage device. We then propose a practical and secure user authentication scheme, capable of supporting the use of the common storage device, which retains all the advantages of schemes using smart cards.     

Microinjection molded disposable microfluidic lab-on-a-chip for efficient detection of agglutination

Previous diagnosing methods based on agglutination have a limitation in view of emergency and point-of-care diagnoses due to the requirement of large scale equipments and much agglutination time. In this paper, we propose a low cost microfluidic lab-on-a-chip for more efficient detection of agglutination. In the present lab-on-a-chip, two inlet microwells, flow guiding microchannels, chaotic micromixer and reaction microwell are fully integrated. Mold inserts for the lab-on-a-chip were manufactured by UV photolithography and nickel electroplating process. The complete lab-on-a-chip was realized by the microinjection molding of cyclic olefin copolymer and the subsequent thermal bonding. The improved serpentine laminating micromixer, developed by our group, integrated in the lab-on-a-chip showed the high-level of chaotic mixing, thereby enabling us to get a reliable mixing of sample and reagent. The performance of the fabricated lab-on-a-chip was demonstrated by agglutination experiments with simulated bloods of 10 μl and simulated sera of 10 μl. The results of agglutination inside the reaction microwell were clearly read by means of the level of light transmission. The present microfluidic lab-on-a-chip could be widely applied to various clinical diagnostics based on agglutination tests.     

Situation reactive approach to Vendor Managed Inventory problem

In this research, we deal with VMI (Vendor Managed Inventory) problem where one supplier is responsible for managing a retailer’s inventory under unstable customer demand situation. To cope with the nonstationary demand situation, we develop a retrospective action-reward learning model, a kind of reinforcement learning techniques, which is faster in learning than conventional action-reward learning and more suitable to apply to the control domain where rewards for actions vary over time. The learning model enables the inventory control to become situation reactive in the sense that replenishment quantity for the retailer is automatically adjusted at each period by adapting to the change in customer demand. The replenishment quantity is a function of compensation factor that has an effect of increasing or decreasing the replenishment amount. At each replenishment period, a cost-minimizing compensation factor value is chosen in the candidate set. A simulation based experiment gave us encouraging results for the new approach.     

Impact of noise on self-rated job satisfaction and health in open-plan offices: a structural equation modelling approach

This study uses a structural equation model to examine the effects of noise on self-rated job satisfaction and health in open-plan offices. A total of 334 employees from six open-plan offices in China and Korea completed a questionnaire survey. The questionnaire included questions assessing noise disturbances and speech privacy, as well as job satisfaction and health. The results indicated that noise disturbance affected self-rated health. Contrary to popular expectation, the relationship between noise disturbance and job satisfaction was not significant. Rather, job satisfaction and satisfaction with the environment were negatively correlated with lack of speech privacy. Speech privacy was found to be affected by noise sensitivity, and longer noise exposure led to decreased job satisfaction. There was also evidence that speech privacy was a stronger predictor of satisfaction with environment and job satisfaction for participants with high noise sensitivity. In addition, fit models for employees from China and Korea showed slight differences.

Practitioner Summary: This study is motivated by strong evidence that noise is the key source of complaints in open-plan offices. Survey results indicate that self-rated job satisfaction of workers in open-plan offices was negatively affected by lack of speech privacy and duration of disturbing noise.     

A small‐area and low‐power data driver IC using two‐stage DAC with a capacitor array for active matrix flat‐panel displays

A small‐area and low‐power data driver integrated circuit (IC) using a two‐stage digital‐to‐analog converter (DAC) with a capacitor array is proposed for active matrix flat‐panel displays. The proposed data driver IC employs a capacitor array in the two‐stage DAC so as to reduce the DAC area and eliminate the need for a resistor string, which has high‐power consumption. To verify the proposed two‐stage DAC, a 20‐channel data driver IC with the proposed 10‐bit two‐stage DAC was fabricated using a 0.18‐μm complementary metal–oxide–semiconductor process with 1.8 and 6 V complementary metal–oxide–semiconductor devices. The proposed 10‐bit two‐stage DAC occupies only 43.8% of the area of a conventional 10‐bit two‐stage DAC. The measurement results show that the differential nonlinearity and integral nonlinearity are +0.58/?0.52 least significant bit and +0.62/?0.59 least significant bit, respectively. The measured interchannel deviation of the voltage outputs is 8.8 mV, and the measured power consumption of the 20‐channel data driver IC is reduced to 7.1 mW, which is less than half of the power consumed by the conventional one.     

Robust multiscale stereo matching from fundus images with radiometric differences

A robust multiscale stereo matching algorithm is proposed to find reliable correspondences between low contrast and weakly textured retinal image pairs with radiometric differences. Existing algorithms designed to deal with piecewise planar surfaces with distinct features and Lambertian reflectance do not apply in applications such as 3D reconstruction of medical images including stereo retinal images. In this paper, robust pixel feature vectors are formulated to extract discriminative features in the presence of noise in scale space, through which the response of low-frequency mechanisms alter and interact with the response of high-frequency mechanisms. The deep structures of the scene are represented with the evolution of disparity estimates in scale space, which distributes the matching ambiguity along the scale dimension to obtain globally coherent reconstructions. The performance is verified both qualitatively by face validity and quantitatively on our collection of stereo fundus image sets with ground truth, which have been made publicly available as an extension of standard test images for performance evaluation.     

Securing against brute-force attack: A hash-based RFID mutual authentication protocol using a secret value

Radio Frequency IDentification (RFID ) system is a contactless automatic identification system using small, low-cost RFID tags. It enables recognition of the tag information via radio frequency communication, by attaching an RFID tag to an animate or inanimate object. Since an RFID system has the advantage of simultaneously recognizing massive amounts of information, it is expected to replace the bar-code system. The most important problem with an RFID system is that an adversary can access the tag information, which gives rise to privacy and forgery problems. This paper presents a hash-based mutual authentication protocol as a solution. The proposed protocol is designed to send a random number generated by a tag to a back-end server without disclosure. Moreover it substitutes a random number with a secret value, which is employed in a response message. The properties of the proposed protocol enable constant creation of distinct response messages without interferences from intended or meaningless requests generated by an adversary, while the secret value is not directly transmitted. Our proposed protocol make is difficult for an attacker to launch successful brute-force attacks against our approach.     

Effect of control-to-display gain and movement direction of information spaces on the usability of navigation on small touch-screen interfaces using tap-n-drag

Tap-n-drag is a popular navigation method for small touch-screen interfaces. When an information space is too large compared to the touch-screen size, navigating the information space using tap-n-drag requires too many drags, resulting in poor usability such as long navigation time or fatigue. In this study, the effect of control-to-display gain on the usability of tap-n-drag was experimentally investigated to determine whether increasing the control-to-display gain can resolve this problem. The effect of movement direction of the information space relative to the drag direction was also investigated (push background vs. push viewport). In experiments, increasing control-to-display gain seemed to increase the usability of tap-n-drag, but excessively large gain seemed to have the opposite effect on some measures such as task completion time, ease of use and overall preference; as a result these measures-vs.-GAIN curves were U-shaped or inverted-U-shaped. Overall, both task completion time and number of touches required to locate a target were lower when using push viewport than when using push background, except at GAIN = 1.

Relevance to industry

The results of this study can be used to enhance the usability of tap-n-drag and other navigation methods in small touch-screen devices when users navigate a large information space.