Background and aimsThe nine-item Internet Gaming Disorder Scale – Short Form (IGDS-SF9) is brief and effective to evaluate Internet Gaming Disorder (IGD) severity. Although its scores show promising psychometric properties, less is known about whether different groups of gamers interpret the items similarly. This study aimed to verify the construct validity of the Persian IGDS-SF9 and examine the scores in relation to gender and hours spent online gaming among 2,363 Iranian adolescents.MethodsConfirmatory factor analysis (CFA) and Rasch analysis were used to examine the construct validity of the IGDS-SF9. The effects of gender and time spent online gaming per week were investigated by multigroup CFA and Rasch differential item functioning (DIF).ResultsThe unidimensionality of the IGDS-SF9 was supported in both CFA and Rasch. However, Item 4 (fail to control or cease gaming activities) displayed DIF (DIF contrast = 0.55) slightly over the recommended cutoff in Rasch but was invariant in multigroup CFA across gender. Items 4 (DIF contrast = −0.67) and 9 (jeopardize or lose an important thing because of gaming activity; DIF contrast = 0.61) displayed DIF in Rasch and were non-invariant in multigroup CFA across time spent online gaming.ConclusionsGiven the Persian IGDS-SF9 was unidimensional, it is concluded that the instrument can be used to assess IGD severity. However, users of the instrument are cautioned concerning the comparisons of the sum scores of the IGDS-SF9 across gender and across adolescents spending different amounts of time online gaming.

Owing to the low cost and convenience of identifying an object without physical contact, Radio Frequency Identification (RFID) systems provide innovative, promising and efficient applications in many domains. An RFID grouping protocol is a protocol that allows an off-line verifier to collect and verify the evidence of two or more tags simultaneously present. Recently, Huang and Ku (J. Med. Syst, 2009) proposed an efficient grouping protocol to enhance medication safety for inpatients based on low-cost tags. However, the Huang-Ku scheme is not secure; an attacker can easily make up fake grouping records to cheat the verifier. This weakness would seriously endanger the safety of inpatient medication safety. This paper will show the weaknesses, and then propose two RFID-based solutions to enhance medication safety for two different scenarios. The proposed schemes are practical, secure and efficient for medication applications.

The linear relationship between Rasch scores and domain scores suggested that the current calculations for domain scores were applicable and without serious bias. Clinical practitioners may regularly collect and record the WHOQOL-BREF domain scores into electronic health records.

A remote password authentication scheme based on the Chinese remainder theorem is proposed. The scheme can verify the remote password without verification tables. In the initial phase, the password generation centre generates and assigns a password corresponding to each user. The ideas of smart cards and the identitybased signature scheme introduced by Shamir are employed in this phase. Each user possesses a smart card for later login and authentication. In the login phase, the user submits the identity and password associated with the smart card. In the authentication phase, the system verifies the remotely submitted password to check if the login request is accepted or rejected. A signature scheme and communication timestamps are provided in the authentication phase against the potential attacks of replaying a previously intercepted login request. 7