Hybrid Spam Filtering for Mobile Communication

Spam messages are an increasing threat to mobile communication. Several mitigation techniques have been proposed, including white and black listing, challenge-response and content-based filtering. However, none are perfect and it makes sense to use a combination rather than just one. We propose an anti-spam framework based on the hybrid of content-based filtering and challenge-response. There is the trade-offs between accuracy of anti-spam classifiers and the communication overhead. Experimental results show how, depending on the proportion of spam messages, different filtering %%@ parameters should be set.Comment: 6 pages, 5 figures, 1 tabl

Ultraviolet photodepletion spectroscopy of dibenzo-18-crown-6-ether complexes with alkali metal cations

Ultraviolet photodepletion spectra of dibenzo-18-crown-6-ether complexes with alkali metal cations (M+-DB18C6, M = Cs, Rb, K, Na, and Li) were obtained in the gas phase using electrospray ionization quadrupole ion-trap reflectron time-of-flight mass spectrometry. The spectra exhibited a few distinct absorption bands in the wavenumber region of 35450−37800 cm^(−1). The lowest-energy band was tentatively assigned to be the origin of the S_0-S_1 transition, and the second band to a vibronic transition arising from the “benzene breathing” mode in conjunction with symmetric or asymmetric stretching vibration of the bonds between the metal cation and the oxygen atoms in DB18C6. The red shifts of the origin bands were observed in the spectra as the size of the metal cation in M^+-DB18C6 increased from Li^+ to Cs^+. We suggested that these red shifts arose mainly from the decrease in the binding energies of larger-sized metal cations to DB18C6 at the electronic ground state. These size effects of the metal cations on the geometric and electronic structures, and the binding properties of the complexes at the S_0 and S_1 states were further elucidated by theoretical calculations using density functional and time-dependent density functional theories

Impact of non-pharmaceutical interventions on the rate of respiratory viruses other than severe acute respiratory syndrome coronavirus 2 in the coronavirus disease 2019 pandemic

Purpose We aimed to evaluate the impact of non-pharmaceutical interventions (NPIs) on the transmission of respiratory viruses other than severe acute respiratory syndrome coronavirus 2 among children during the coronavirus disease 2019 pandemic. Methods We analyzed the clinical and polymerase chain reaction (PCR) findings using electronic medical records of children (< 18 years) with fever or respiratory symptoms who were hospitalized via the emergency department of Wonkwang University Hospital (Iksan, Korea), from March 2018 through December 2021. The children were divided into before and after groups based on the hospitalization date relative to February 2020, starting point of the implementation of NPIs. PCR was performed using nasopharyngeal swab samples. Between the 2 groups, we compared age, sex, length of hospital stay, and PCR findings. Results The before and after groups consisted of 3,160 and 989, respectively, showing a 68.7% decrease in the number of children undergoing PCRs after the implantation of NPIs. The after group showed higher median values of the age and length of hospital stay than the before group (Ps < 0.001). A 76.9% decrease was noted in the number of children having PCR positivities (from 1,101 [34.8%] to 254 [25.7%]; P < 0.001). Among detected viruses, an increase in the proportion was noted only in human bocavirus (from 81 [2.6%] to 54 [5.5%]; P < 0.001). In contrast, significant decreases in the proportions were found in adenovirus, enterovirus, influenza A and B, respiratory syncytial viruses A and B, human coronaviruses (229E, NL63, and OC43) and human metapneumovirus. Conclusion NPIs may be effective in reducing the transmission of respiratory viruses other than severe acute respiratory syndrome coronavirus 2 among children during the pandemic

Application of Computational Lower Extremity Model to Investigate Different Muscle Activities and Joint Force Patterns in Knee Osteoarthritis Patients during Walking

Many experimental and computational studies have reported that osteoarthritis in the knee joint affects knee biomechanics, including joint kinematics, joint contact forces, and muscle activities, due to functional restriction and disability. In this study, differences in muscle activities and joint force patterns between knee osteoarthritis (OA) patients and normal subjects during walking were investigated using the inverse dynamic analysis with a lower extremity musculoskeletal model. Extensor/flexor muscle activations and torque ratios and the joint contact forces were compared between the OA and normal groups. The OA patients had higher extensor muscle forces and lateral component of the knee joint force than normal subjects as well as force and torque ratios of extensor and flexor muscles, while the other parameters had little differences. The results explained that OA patients increased the level of antagonistic cocontraction and the adduction moment on the knee joint. The presented findings and technologies provide insight into biomechanical changes in OA patients and can also be used to evaluate the postoperative functional outcomes of the OA treatments