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Optimizing election logistics: A multi-period routing problem embedding time-dependent reward functions
No full textWith the 2024 US Presidential Election now concluded, the growing complexity of designing effective election campaigns has become clearer. Motivated by the logistical challenges associated with US election campaigns, we introduce the Reward-driven Multi-period Politician Routing Problem. It involves diverse politicians planning their campaigns over multiple days, considering constraints such as clustered locations, time-and location-dependent rewards, budget limits, mandatory rest days, and flexible daily routes that can be either open or closed, with starting and ending locations not known in advance. We model the problem as a mixed-integer linear program, complemented with several valid inequalities, and innovate by designing new subtour elimination techniques that jointly deal with open and closed paths. We developed 36 new benchmark instances tailored to the US presidential elections. To tackle large-sized instances, we develop a Sequential Route Construction Matheuristic that exploits the multi-period structure of the problem to provide efficient and effective solutions. We incorporate time-dependent reward profiles (concave, convex, linearly decreasing, linearly increasing, and periodic) into the objective function to capture diverse decision-making perspectives. Experimental results show interesting computational issues on the different tested models and the impact of the chosen reward profile on their performance.Publisher versio
Better reflective functioning in mothers linked to longer joint attention with infants
No full textJoint attention is a foundational precursor to later developmental outcomes such as vocabulary, intelligence, and theory of mind. Previous research has shown that maternal sensitivity, depressive symptoms, and parent-child attachment security are associated with attention-sharing behaviors between mothers and their infants. The present study examined the relationship between mothers’ reflective functioning (the ability to recognize and interpret one’s own and one’s child’s mental states, as well as the behaviors motivated by those mental states) and joint attention. Data were collected from 72 infants aged 10–16 months and their mothers. Results indicated that mothers who reported greater difficulty in understanding and distinguishing between their own and their child's mental states (i.e., higher prementalization) tended to engage in joint attention episodes that were shorter and more frequent, and they were also more likely to terminate these interactions. In contrast, mothers expressing greater interest and curiosity about their infants’ mental states spent longer periods in joint attention, initiated these episodes less often, and were less inclined to terminate them. Additionally, mothers who felt more certain about their infants’ mental states were less likely to end joint attention episodes. After controlling for infant age and socioeconomic status, higher levels of interest and certainty continued to predict lower maternal termination, while prementalization was still linked to a higher number of joint attention episodes. These findings suggest that mothers’ perceptions of their infants’ mental states shape how they engage in shared attention during everyday play interactions
Migration and local innovation: Evidence from fine-grained data from oecd countries
No full textDoes the presence of migrants influence innovation at the local level? This paper answers this question using novel data containing fine-grained information on the migrant population and geo-coded data on patent locations for a large set of 19 OECD countries over the 1990–2014 period. We find that a one percentage point increase in the local migrant share increases patent applications by 2.5%. This effect is driven by more urbanised and economically developed localities, where innovation levels are already higher to begin with. However, this impact becomes insignificant when aggregating observations at larger geographical levels, suggesting that the effect of migration on innovation is concentrated in space and features high rates of spatial decay. © 2025Publisher versio
Modelling nonlinear site coefficients and predominant periods for southern coasts of İstanbul by geotechnical downhole arrays
No full textThis study investigates nonlinear response spectral amplification factors (RSAF) and predominant periods (T-p) for the southern coast of the Istanbul's European Side by employing a Monte Carlo simulation-based approach. The methodology incorporates one dimensional (1D) site response analyses of simulated random shear wave velocity (V-s) profiles, along with the optimization of these profiles through least-squares error between the response spectra of recorded weak ground motions and the modelled ones. The recorded ground motions were selected from a database of near-field earthquakes with epicentral distances R-epi < 100 km and magnitudes in the range 3.9 = 4.8, a scaling procedure for bedrock PGAs was applied to model the nonlinear RSAF and T-p. In this study, the local site coefficients specified in TEBC (2018) were tested for the southern coastal soils of the Istanbul's European side for the first time, an area broadly characterized by poor soil conditions (i.e., time averaged shear wave velocity for the top 30 m, 180 < V-s30 < 360 m/s). The findings indicate that the estimated RSAFs (i.e., local site coefficients) particularly at 1.0 s period (T = 1.0 s), exceed those defined in TEBC (2018). Furthermore, the T-p values at seismic station locations under weak amplitude ground motions differ substantially from those under strong ground motions. The in-situ methods (e.g., microtremor, etc.) for determining the site T-p may be misleading, as they primarily capture linear behavior. The proposed method provides a basis for revising the short-period (T = 0.2 s) and 1.0 s period RSAFs in TEBC (2018) and highlights T-p variations for the loose granular and clayey soils of Istanbul
