Suns-VOC_\textrm{OC} characteristics of high performance kesterite solar cells

Low open circuit voltage ($V_{OC}$) has been recognized as the number one problem in the current generation of Cu$_{2}$ZnSn(Se,S)$_{4}$ (CZTSSe) solar cells. We report high light intensity and low temperature Suns-$V_{OC}$ measurement in high performance CZTSSe devices. The Suns-$V_{OC}$ curves exhibit bending at high light intensity, which points to several prospective $V_{OC}$ limiting mechanisms that could impact the $V_{OC}$, even at 1 sun for lower performing samples. These V$_{OC}$ limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-$V_{OC}$ measurements with different monochromatic illumination. These limiting factors may also contribute to an artificially lower $J_{SC}$-$V_{OC}$ diode ideality factor.Comment: 9 pages, 9 figures, 1 supplementary materia

House Allocation with Existing Tenants: An Equivalence

In this paper we analyze two house allocation mechanisms each of which is designed to eliminate inefficiencies in real-life house allocation problems where there are both existing tenants and newcomers. The first mechanism chooses the unique core allocation of a "sister" exchange economy which is constructed by assigning each existing tenant her current house and randomly assigning each newcomer a vacant house. The second mechanism -top trading cycles mechanism- first chooses an ordering from a given distribution and next determines the final outcome as follows: Assign first agent her top choice, next agent her top choice among remaining houses and so on, until someone demands house of an existing tenant who is still in the line. At that point modify the queue by inserting her at the top and proceed. Similarly, insert any existing tenant who is not already served at the top of the queue once her house is demanded. Whenever a loop of existing tenants forms, assign each of them the house she demands and proceed. Our main result is that the core based mechanism is equivalent to an extreme case of the top trading cycles mechanism which orders newcomers before the existing tenants.

Course Bidding at Business Schools

Mechanisms that rely on course bidding are widely used at Business Schools in order to allocate seats at oversubscribed courses. Bids play two key roles under these mechanisms: Bids are used to infer student preferences and bids are used to determine who have bigger claims on course seats. We show that these two roles may easily conflict and preferences induced from bids may significantly differ from the true preferences. Therefore while these mechanisms are promoted as market mechanisms, they do not necessarily yield market outcomes. The two conflicting roles of bids is a potential source of efficiency loss part of which can be avoided simply by asking students to state their preferences in addition to bidding and thus "separating" the two roles of the bids. While there may be multiple market outcomes under this proposal, there is a market outcome which Pareto dominates any other market outcome.

Efficient ConvNets for Analog Arrays

Analog arrays are a promising upcoming hardware technology with the potential to drastically speed up deep learning. Their main advantage is that they compute matrix-vector products in constant time, irrespective of the size of the matrix. However, early convolution layers in ConvNets map very unfavorably onto analog arrays, because kernel matrices are typically small and the constant time operation needs to be sequentially iterated a large number of times, reducing the speed up advantage for ConvNets. Here, we propose to replicate the kernel matrix of a convolution layer on distinct analog arrays, and randomly divide parts of the compute among them, so that multiple kernel matrices are trained in parallel. With this modification, analog arrays execute ConvNets with an acceleration factor that is proportional to the number of kernel matrices used per layer (here tested 16-128). Despite having more free parameters, we show analytically and in numerical experiments that this convolution architecture is self-regularizing and implicitly learns similar filters across arrays. We also report superior performance on a number of datasets and increased robustness to adversarial attacks. Our investigation suggests to revise the notion that mixed analog-digital hardware is not suitable for ConvNets

Room Assignment-Rent Division: A Market Approach

A group of friends consider renting a house but they shall first agree on how to allocate its rooms and share the rent. We propose an auction mechanism for room assignment-rent division problems which mimics the market mechanism. Our auction mechanism is efficient, envy-free, individually-rational and it yields a non-negative price to each room whenever that is possible with envy-freeness.

The five factor personality traits and subjective well-being

Bu araştırmanın amacı kişilik özellikleri ve öznel iyi oluş arasındaki ilişkileri incelemektir. Araştırmanın katılımcılarını 234 kişi (98 kadın/136 erkek) oluşturmaktadır. Çalışma grubunun yaş aralığı 18-61’dir. Çalışmada veri toplama araçları olarak Oxford Mutluluk Ölçeği-Kısa Formu ve Beş Faktör Kişilik Ölçeği kullanılmıştır. Çalışmadan elde edilen bulgulara göre nevrotik kişilik özelliği ile öznel iyi oluş arasında negatif yönde anlamlı bir ilişki bulunmuştur. Dışadönüklük, sorumluluk, yumuşak başlılık ve deneyime açıklık kişilik özellikleriyle öznel iyi oluş arasında ise pozitif yönde anlamlı ilişkiler bulunmuştur. Ayrıca nevrotik kişilik özelliğinin öznel iyi oluşu negatif yönde; dışadönüklük kişilik özelliğinin ise pozitif yönde anlamlı düzeyde yordadığı sonucuna ulaşılmıştır.The aim of this research is to analyze the relations between personality traits and subjective well-being. The number of the participants of the research was 234 (98 women/136 men). The age range of the study group was 18-61. The Oxford Happiness Scale-Short Form and the Big Five Personality Scale were used. Findings showed that there was a significantly negative relationship between neurotic personality trait and subjective well-being. Findings also revealed that there were positive relationships between subjective well-being and extraversion, conscientiousness, agreeableness, openness. Besides, it was found that neurotic personality trait was a negative and extraversion was a positive predictor of subjective well-being