The Spatial Arrangement of Urban Activities: A Simultaneous Location Model

1976 ◽  
Vol 8 (7) ◽  
pp. 779-791 ◽  
Author(s):  
J Odland

The spatial patterns of urban activities are treated as the outcome of a balance between economic conditions that reward spatial concentration of employment activity on the one hand but favor spatial dispersion of residences on the other. The balance between these two sets of conditions is mediated by the cost of commuting. These three elements are formalized in terms of a mathematical-programming model that determines simultaneously the location patterns of employment, residential activity, and commuting. The solution conditions lead to a single-equation model which estimates the distances between zones in a city on the basis of their residential and employment densities. This version is fitted to data for four US cities. Estimates derived from the single-equation model can be resolved into two-dimensional maps of the zones by multidimensional scaling, and maps of the four cities, based on the estimated equations, are obtained and compared with the actual maps of the cities. The results indicate that the estimated parameters are congruent with the actual spatial arrangements of the cities.

2021 ◽  
Vol 13 (4) ◽  
pp. 1628
Author(s):  
Xiaoxu Dong ◽  
Cheon Yu ◽  
Yun Seop Hwang

This study investigates how reverse knowledge spillover (RKS) generated through outward foreign direct investment (OFDI) promotes sustainable development in an investment home country. Economic, social, and environmental dimensions are the pillars of sustainable development and their indicators are developed upon the concept of institutional quality. To this end, we use a balanced panel of 30 Chinese Mainland provinces from 2003 to 2016 and employ a simultaneous equation model to analyze the data in order to observe the direct and indirect effects of OFDI-induced RKS on sustainable development. The current study adopts several indicators to capture the economic, social, and environmental aspects of sustainable development. Additionally, we classify RKS into two types, given the investment destinations in terms of developed economies and emerging economies. On the one hand, our findings confirm that OFDI-induced RKS from developed economies facilitates domestic innovation but negatively affects progress on social and environmental development. On the other hand, OFDI-induced RKS from emerging economies is not conducive to domestic innovation, but it directly fosters sustainable development.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3611
Author(s):  
Sandra Gonzalez-Piedra ◽  
Héctor Hernández-García ◽  
Juan M. Perez-Morales ◽  
Laura Acosta-Domínguez ◽  
Juan-Rodrigo Bastidas-Oyanedel ◽  
...  

In this paper, a study on the feasibility of the treatment of raw cheese whey by anaerobic co-digestion using coffee pulp residues as a co-substrate is presented. It considers raw whey generated in artisanal cheese markers, which is generally not treated, thus causing environmental pollution problems. An experimental design was carried out evaluating the effect of pH and the substrate ratio on methane production at 35 °C (i.e., mesophilic conditions). The interaction of the parameters on the co-substrate degradation and the methane production was analyzed using a response surface analysis. Furthermore, two kinetic models were proposed (first order and modified Gompertz models) to determine the dynamic profiles of methane yield. The results show that co-digestion of the raw whey is favored at pH = 6, reaching a maximum yield of 71.54 mLCH4 gVSrem−1 (31.5% VS removed) for raw cheese whey and coffee pulp ratio of 1 gVSwhey gVSCoffe−1. The proposed kinetic models successfully fit the experimental methane production data, the Gompertz model being the one that showed the best fit. Then, the results show that anaerobic co-digestion can be used to reduce the environmental impact of raw whey. Likewise, the methane obtained can be integrated into the cheese production process, which could contribute to reducing the cost per energy consumption.


Author(s):  
Frederico Finan ◽  
Maurizio Mazzocco

Abstract Politicians allocate public resources in ways that maximize political gains, and potentially at the cost of lower welfare. In this paper, we quantify these welfare costs in the context of Brazil’s federal legislature, which grants its members a budget to fund public projects within their states. Using data from the state of Roraima, we estimate a model of politicians’ allocation decisions and find that 26.8% of the public funds allocated by legislators are distorted relative to a social planner’s allocation. We then use the model to simulate three potential policy reforms to the electoral system: the adoption of approval voting, imposing a one-term limit, and redistricting. We find that a one-term limit and redistricting are both effective at reducing distortions. The one-term limit policy, however, increases corruption, which makes it a welfare-reducing policy.


2021 ◽  
Vol 11 (4) ◽  
pp. 1970
Author(s):  
Martin Lasota ◽  
Petr Šidlof ◽  
Manfred Kaltenbacher ◽  
Stefan Schoder

In an aeroacoustic simulation of human voice production, the effect of the sub-grid scale (SGS) model on the acoustic spectrum was investigated. In the first step, incompressible airflow in a 3D model of larynx with vocal folds undergoing prescribed two-degree-of-freedom oscillation was simulated by laminar and Large-Eddy Simulations (LES), using the One-Equation and Wall-Adaptive Local-Eddy (WALE) SGS models. Second, the aeroacoustic sources and the sound propagation in a domain composed of the larynx and vocal tract were computed by the Perturbed Convective Wave Equation (PCWE) for vowels [u:] and [i:]. The results show that the SGS model has a significant impact not only on the flow field, but also on the spectrum of the sound sampled 1 cm downstream of the lips. With the WALE model, which is known to handle the near-wall and high-shear regions more precisely, the simulations predict significantly higher peak volumetric flow rates of air than those of the One-Equation model, only slightly lower than the laminar simulation. The usage of the WALE SGS model also results in higher sound pressure levels of the higher harmonic frequencies.


2020 ◽  
Vol 17 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Florian Mundhenke

Audience research proves that possibilities of interaction in i-docs are often not fulfilled by the user, who is not really part of a ‘work in progress’ (as intended by the makers). With the shift and development of new digital formats (360-degree-films, nonfictional VR experiences, AR apps), the question of the possible interactive potential should be addressed once again. Since VR projects are fully immersive (mostly using head-mounted displays), there is no possible distraction from outside on the one hand. On the other hand, there is a shift from the computer game style aesthetic of early i-docs, with their pure spatial arrangement of events, to a more inclusive digital storytelling modality with the user experiencing his own world-building. This will be discussed with taking into consideration the non-fictional VR experience as a mode of actively combining immersion and storytelling for a satisfactory user experience. Afterwards two very different examples of nonfictional VR production will be presented, and their modalities will be briefly touched; the utilized approach and its user response will be discussed. A look at the future of possible developments concludes the essay.


Author(s):  
Josu Doncel ◽  
Nicolas Gast ◽  
Bruno Gaujal

We analyze a mean field game model of SIR dynamics (Susceptible, Infected, and Recovered) where players choose when to vaccinate. We show that this game admits a unique mean field equilibrium (MFE) that consists in vaccinating at a maximal rate until a given time and then not vaccinating. The vaccination strategy that minimizes the total cost has the same structure as the MFE. We prove that the vaccination period of the MFE is always smaller than the one minimizing the total cost. This implies that, to encourage optimal vaccination behavior, vaccination should always be subsidized. Finally, we provide numerical experiments to study the convergence of the equilibrium when the system is composed by a finite number of agents ( $N$ ) to the MFE. These experiments show that the convergence rate of the cost is $1/N$ and the convergence of the switching curve is monotone.


2021 ◽  
Author(s):  
Mircea-Adrian Digulescu

It has long been known that cryptographic schemes offering provably unbreakable security exist, namely the One Time Pad (OTP). The OTP, however, comes at the cost of a very long secret key - as long as the plain-text itself. In this paper we propose an encryption scheme which we (boldly) claim offers the same level of security as the OTP, while allowing for much shorter keys, of size polylogarithmic in the computing power available to the adversary. The Scheme requires a large sequence of truly random words, of length polynomial in the both plain-text size and the logarithm of the computing power the adversary has. We claim that it ensures such an attacker cannot discern the cipher output from random data, except with small probability. We also show how it can be adapted to allow for several plain-texts to be encrypted in the same cipher output, with almost independent keys. Also, we describe how it can be used in lieu of a One Way Function.


Author(s):  
Agustina Malvido Perez Carletti ◽  
Markus Hanisch ◽  
Jens Rommel ◽  
Murray Fulton

AbstractIn this paper, we use a unique data set of the prices paid to farmers in Argentina for grapes to examine the prices paid by non-varietal wine processing cooperatives and investor-oriented firms (IOFs). Motivated by contrasting theoretical predictions of cooperative price effects generated by the yardstick of competition and property rights theories, we apply a multilevel regression model to identify price differences at the transaction level and the departmental level. On average, farmers selling to cooperatives receive a 3.4 % lower price than farmers selling to IOFs. However, we find cooperatives pay approximately 2.4 % more in departments where cooperatives have larger market shares. We suggest that the inability of cooperatives to pay a price equal to or greater than the one paid by IOFs can be explained by the market structure for non-varietal wine in Argentina. Specifically, there is evidence that cooperative members differ from other farmers in terms of size, assets and the cost of accessing the market. We conclude that the analysis of cooperative pricing cannot solely focus on the price differential between cooperatives and IOFs, but instead must consider other factors that are important to the members.


Traditio ◽  
1948 ◽  
Vol 6 ◽  
pp. 161-185
Author(s):  
Kurt Lewent

Cerveri was decidedly no poetical genius, and often enough he follows the trodden paths of troubadour poetry. However, there is no denying that again and again he tries to escape that poetical routine. In many cases these attempts result in odd and eccentric compositions, where the unusual is reached at the cost of good taste and poetical values. On the other hand, it must be admitted that Cerveri's efforts in this respect were not always futile. His is, e.g. an amusing satire upon bad women. One of his love songs, characteristically called libel by the MS (Sg), assumes the form of a complaint submitted to the king as the supreme earthly judge, in which the defendant is the lady whose charms torture the lover and have made him a prisoner. This poem combines the traditional praise of the beloved and a flattery addressed to the king. Its slightly humoristic tone is also found in a song entitled lo vers del vassayll leyal. Here Cerveri, basing himself on a certain legend connected with St. Mark, gives the king advice in his love affair. Again the poet kills two birds with one stone, flattering the sovereign and pointing, for obvious purposes, to his own poverty. The latter is the only topic of a remarkably personal poem in which the author complains bitterly that, while many of his playmates have become rich in later years, the only wealth he himself did amass were the chans gays and sonetz agradans which he composed for other people to enjoy. Cerveri even tries to renew the traditional genre of the chanson de la mal mariée by adding motifs of—presumably—his own invention. This tendency towards a more independent way of thinking and greater originality in its poetical presentation could not be better illustrated than by the two poems which the MS calls Lo vers de la terra de Preste Johan and Pistola The one puts the poet's moral argumentation against the background of the medieval legend of Prester John, the other, which forms the subject of the present study, sets its teachings in a still more solemn framework, the liturgy of the Mass.


Sign in / Sign up

Export Citation Format

Share Document