Adaptive immunity based reinforcement learning

Recently much attention has been paid to intelligent systems which can adapt themselves to dynamic and/or unknown environments by the use of learning methods. However, traditional learning methods have a disadvantage that learning requires enormously long amounts of time with the degree of complexity of systems and environments to be considered. We thus propose a novel reinforcement learning method based on adaptive immunity. Our proposed method can provide a near-optimal solution with less learning time by self-learning using the concept of adaptive immunity. The validity of our method is demonstrated through some simulations with Sutton’s maze problem. This work was present in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Prediction of human eye movements in facial discrimination tasks

Under natural viewing conditions, human observers selectively allocate their attention to subsets of the visual input. Since overt allocation of attention appears as eye movements, the mechanism of selective attention can be uncovered through computational studies of eyemovement predictions. Since top-down attentional control in a task is expected to modulate eye movements significantly, the models that take a bottom-up approach based on low-level local properties are not expected to suffice for prediction. In this study, we introduce two representative models, apply them to a facial discrimination task with morphed face images, and evaluate their performance by comparing them with the human eye-movement data. The result shows that they are not good at predicting eye movements in this task.     

Comparison of crossing-over between 30-minute drip infusion vs 30-second injection of granisetron for nausea and vomitting with cisplatin

Recently, Granisetron (KYT) was proved to have a strong effect for cisplatin (CDDP)-induced emesis. We compared the effect of KYT for CDDP-induced emesis between two different administration schedules. Forty micrograms/kg of KYT was administered either by 30-minute drip infusion with 100 ml of saline (Group A) or 30-second injection with 10 ml of saline (Group B). We investigated the therapeutic effect of KYT in both group A and Group B by the crossing-over method. After the patients who had a malignant tumor and were going to receive CDDP (over 50 mg/m2) in two courses were selected, KYT was administered by the method of Group A or Group B in a double-blind comparison. The clinical efficacy was at least "effective" in 70% (7/10) of Group A and Group B. The study treatment was considered "useful" in 80% (8/10) of Group A, 90% (9/10) of Group B, and "safe" in 100% of Group A and B. There was no difference between two groups in this respect. The results showed that the slow intravenous injection of KYT also has an excellent antiemetic effect on CDDP-induced emesis and a high degree of safety.     

Learning to mimic programmers gaze behavior for program comprehension improvement

Artificial Life and Robotics - Gaze behavior of human coders could allow to improve programmer-aiding tools relying on program comprehension algorithms, as gaze reveals which subsets of source code...     

Deep MAnTra: deep learning-based multi-animal tracking for Japanese macaques

Artificial Life and Robotics - Multi-instance object tracking is an active research problem in computer vision, where most novel methods analyze and locate targets on videos taken from static...     

Work schedule differences in sleep problems of nursing home caregivers

Nursing home caregivers (n=775; 604 women; mean age 33.6 years) were studied to examine how work schedules affect their sleep. The shift group (n=536) worked under a rotating two-shift system (n=365), a rotating three-shift system (n=66), or other types of shifts (n=78). The non-shift group included 222 caregivers. Participants completed a questionnaire about working conditions, sleep problems, health, lifestyle, and demographic factors. The two-shift caregivers reported the highest levels of difficulty initiating sleep (DIS, 37.6%), insomnia symptoms (43.0%), and poor quality of sleep (24.9%) among the groups. Adjusted odds ratios for these problems were significantly greater for the two-shift caregivers than for non-shift counterparts: DIS (odds ratio 2.86, 95% confidence interval 1.57-5.20), insomnia symptoms (2.33, 1.36-4.02), and poor sleep quality (2.15, 1.09-4.22). Our data suggest that working under a rotating two-shift system, which has a longer night shift, is associated with an elevated risk of sleep problems for nursing home caregivers.     

Broadband robust PWM power amplifier using approximate 2DOF digital control

Recently, it has been found that the bandwidth of pulse-width modulation (PWM) power amplifiers needs to be extended, for example, in an application for testing the power supply of a low-frequency immunity examination or a class-D amplifier. In this article, we show that the bandwidth of a PWM power amplifier can be extended by using an approximate 2DOF digital controller. This controller is implemented in digital signal processing (DSP). It is demonstrated by experiments that the bandwidth can be made wider with this controller.     

Dynamics of iron-ascorbate-induced lipid peroxidation in charged and uncharged phospholipid vesicles

Peroxidation of egg yolk phosphatidylcholine (egg PC) liposomes was induced by addition of ascorbic acid (AsA) and Fe(II) in the presence of a trace of autoxidized egg PC (PC−OOH), but not in the absence of PC−OOH. PC−OOH was degraded upon addition of AsA and Fe(II) but not of either one alone. The results suggest that PC−OOH is necessary to initiate lipid peroxidation by AsA/Fe(II). AsA oxidation in the bulk water phase was also associated with an increase in lipid peroxidation by AsA/Fe(II) in the presence of PC−OOH, but not in the absence of PC−OOH. Furthermore, the spin probe 12-NS [12-(N-oxyl-4,4′-dimethyloxazolidin-2-yl)stearic acid], which labels the hydrophobic region of dimyristoyl phosphatidylcholine (DMPC) liposomal membranes, was degraded upon addition of AsA and Fe(II) in the presence of PC−OOH, but not in the absence of PC−OOH. These results indicate that the “induction message” that is associated with decreases of PC−OOH and AsA in the initiation step of lipid peroxidation must be transferred from the membrane surface to the inner hydrophobic membrane region. AsA in the bulk phase was oxidized faster and more extensively upon its addition together with Fe(II) to egg PC liposomes than to DMPC liposomes, though the initial content of PC−OOH in the former was 5–10 times lower than in the latter. This suggests that, in egg PC liposomes, the OOH-groups of new PC−OOH generated in the inner membrane regions must become accessible from the surface, enabling reaction with AsA/Fe(II) which in turn would result in an extensive decrease in AsA. By contrast, in DMPC liposomes, that do not generate PC−OOH, AsA is only oxidized slightly in connection with the degradation of the PC−OOH initially present. The effect of surface charges on the membrane surface was also studied to obtain further information on the initiation step of lipid peroxidation. The rate of lipid peroxidation by AsA/Fe(II) or Fe(III) decreased in the order, egg PC liposomes ≫negatively charged egg PC liposomes containing dicetylphosphate>positively charge egg PC liposomes containing stearylamine. The rate of associated AsA oxidation was in the order, egg PC liposomes≫egg PC/stearylamine liposomes>egg PC/dicetylphosphate liposomes. However, in DMPC liposomes that do not generate PC−OOH, the rates of AsA oxidation associated with the reductive cleavage of PC−OOH by AsA/Fe(II) and coupled with the reduction of Fe(III) to Fe(II) were in the order, DMPC liposomes =DMPC/stearylamine liposomes≫DMPC/dicetylphosphate liposomes. These differences in the rates of lipid peroxidation, depending on differences in membrane charge, are discussed in relation to two properties of AsA: (i) its antioxidant property through trapping of lipid radicals and (ii) its prooxidant properties (a) by being an effective iron chelator thus altering the reactivity of iron with oxygen and peroxides and (b) by being an iron reductant and providing a source of Fe(II).     

The roles of risk and ambiguity in the adoption of the system of rice intensification (SRI): evidence from Indonesia

Given the recognized yield-enhancing potential of the System of Rice Intensification (SRI), its low adoption and high discontinuance rates in some locales are puzzling. Combining experimental measures of risk and ambiguity aversion with household-level and plot-level panel data collected in rural Indonesia, this study empirically explores factors shaping SRI’s adoption and discontinuance. Employing multivariate and Heckman probit models to control unobserved heterogeneities, we find that farmers’ risk aversion significantly reduces their likelihood of using all individual SRI practices. However, once the effects of risk aversion on the use of SRI in the previous year are statistically controlled, risk aversion does not significantly explain farmers’ subsequent decisions to continue or discontinue SRI practices. Farmers’ ambiguity preferences play no significant role in decisions to use most practices, except alternate wetting and drying, which requires proper coordination of irrigation among neighboring farmers and thus amplifies the uncertainty of effective implementation. The results also show that access to irrigation is a significant factor in the use of SRI and its continuance. Moreover, as SRI requires greater input of labor and therefore curtails time for alternative household activities, including off-farm work, family composition is a significant factor determining its adoption and continuing use. Although these findings are not necessarily generalizable, our study expands the existing knowledge of factors underlying SRI’s slow diffusion.