Investigating the reward cycle for play in young pigs

A reward cycle for investigating the emotional status in animals has been developed and it requires that animals go through three main phases, i.e. anticipation, consumption and relaxation. The reward cycle has not been tested previously for access to play in pigs. Therefore, the aim of this Master thesis was to investigate if growing pigs showed more behaviours indicative of excitement than pigs that were not allowed to play, performed play in a play arena and showed more behaviours indicative of relaxation after play when they were back to their home pen than pigs that were in their home pen the whole time. Forty undocked piglets (10 litters of Specific Pathogen Free half pure-bred Yorkshire and half hybrids of Yorkshire x Landrace balanced for breed between two treatments were used. From 44 days of age the selected pigs were housed in a weaner stable with four per pen, two castrated males and two females with the most average weights, in their original litter in pens with a size of 6.5 m2 called “home pen”. Within each litter two non-play and two play pigs were randomly selected. Focal animals were individually marked by pig marking spray. After five days of acclimatization to the new environment, four days of training started during which two pigs were allowed to walk to the holding pen (2.0 m2) where they were kept for three minutes. After that the mesh gate opened and the pigs walked in freely to the play arena (5.8 m2) where they stayed for 15 minutes. Two of each of the following objects were used as toys in the play arena: wellingtons, brush, traffic cone, rubber pipe, ball and knotted rope. Half of the piglets had previous experience of objects (i.e. knotted rope, ball and tire) around weaning. Play pigs were observed (instantaneously at 30 s intervals and continuously within each 30 s) 3 min. in the holding pen and 15 min. in the play arena. Non-play pigs were only taken to the holding pen (3 min.) and brought back to their home pen. Play pigs were directly after coming back to the home pen observed for 10 min. and non-play pigs were observed on days without play sessions for 10 min. Statistical analysis was done with Generalized Linear Model for Mixed procedures that tested effect of treatment, time, week, sex and previous toy experience. In the holding pen play pigs performed significantly more locomotor play (P<0.01), play fight (P<0.05), elimination (P<0.01) and had more curled tail position (P<0.01) than non-play pigs. However, non-play pigs performed significantly more explore bar than play pigs (P<0.05) in the holding pen. Pigs of both treatments were numerically more often recorded in zone 1 and orient 1 (i.e. closest proximity to the play arena). In the play arena object play was the most performed play type and then locomotor play which both decreased over time (P<0.001). Social play was the least performed play behaviour but even if it stayed close to zero it showed a slight gradual increase over time (P<0.001). Thus, as predicted they performed all three types of play. The most and the least preferred toys were numerically the brush and the ball respectively. In the home pen play pigs performed significantly more social contact (P<0.001), moving (P<0.001) and exploring (P<0.001), a tendency for drinking more (P<0.1) and significantly less locomotor play (P<0.05) than non-play pigs. In the home pen, non-play pigs performed significantly more lying (P<0.001) and had the tail in a hanging position more (P<0.001). Those behaviours expected to be relaxation-related, such as drinking, eating and rubbing against pen structures, were not significantly higher in play pigs. In conclusion, play pigs showed some behaviours indicative of anticipation in the holding pen, they performed all three types of play in the play arena. However, play pigs did not show behaviours expected to indicate relaxation in the home pen.En belöningscykel för att undersöka det emotionella tillståndet hos djur har utvecklats och den kräver att djur går igenom tre faser, dvs. förväntan, konsumtion och avkoppling. Belöningscykeln har inte testats tidigare för tillgång till lek hos grisar. Syftet med detta examensarbete var att undersöka om växande grisar visade fler beteenden som tyder på förväntan att leka än grisar som inte fick möjlighet att leka, om de utförde lekbeteenden i en lekarena och om de visade flera beteenden som tyder på avkoppling efter lek när de var tillbaka i sin hembox än grisar som var i sin hembox hela tiden. Fyrtio ej svanskuperade smågrisar (10 kullar) av specifikt patogenfria halvt renrasiga Yorkshire och halvt hybrider av Yorkshire x Lantras som balanserades för ras mellan två behandlingar användes. Från 44 dagars ålder hölls de utvalda grisarna i ett avväjningsstall med fyra per box, två kastrerade hanar och två honor med de mest genomsnittliga vikterna, i sin ursprungliga kull i boxar med en storlek på 6,5 m2 kallade "hembox". Inom varje kull valdes slumpmässigt två lekgrisar och två icke-lekgrisar ut. Fokaldjuren märktes individuellt med grismärkspray. Efter fem dagars acklimatisering till den nya miljön, började fyra dagars träning under vilka två grisar fick gå till förväntansboxen (2,0 m2) där de hölls under tre min. Efter att gallergrinden öppnades fick grisarna gå fritt i lekarenan (5,8 m2) där de stannade i 15 min. Två av vart och ett av följande objekt användes som leksaker i lekarenan: stövel, borste, trafikkon, gummirör, boll och knutet rep. Hälften av smågrisarna hade tidigare erfarenhet av objekt (dvs. knutet rep, boll och däck) runt avvänjningen. Lekgrisar observerades (momentant med 30 s intervall och kontinuerligt inom varje 30 s intervall) 3 min. i förväntansboxen och 15 min. i lekarenan. Icke-lek grisar togs endast till förväntansboxen (3 min.) och togs sedan tillbaka till sin hembox. Lekgrisarna observerades 10 min. direkt efter det att de kom tillbaka till hemboxen och icke-lek grisar observerades under 10 min. på dagar utan lek. Statistisk analys gjordes med generaliserad linjär modell för blandade förfaranden och testade effekten av behandling, tid, vecka, kön och tidigare leksakserfarenhet. I förväntansboxen utförde grisarna signifikant mer rörelselek (P<0,01), kamplek (P<0,05), eliminering (P<0,01) och hade mer knorr på svansen (P <0,01) än icke-lek grisar. Men, icke-lek grisar utförde signifikant mer undersökande av gallergrinden än lekgrisarna (P<0,05) i förväntansboxen. Grisar av båda behandlingarna var numeriskt oftare i zon 1 och orientering 1 (dvs. närmast lekarenan). I lekarenan var objektetlek den mest utförda lektypen och sedan rörelselek som båda minskade över tid (P<0,001). Social lek var det minst utförda lekbeteendet, men även om det stannade nära noll visade det en svag successiv ökning över tid (P<0,001). Som förväntat utförde de alla tre typer av lek. De mest och de minst föredragna leksakerna var numeriskt borsten respektive bollen. I hemboxen utförde lekgrisarna signifikant mer social kontakt (P<0,001), förflyttning (P<0,001) och undersökning (P<0,001), en tendens till att dricka mer (P<0,1) och signifikant mindre rörelselek (P<0,05) än icke-lek grisar. I hemboxen utförde icke-lek grisar signifikant mer liggande (P <0,001) och hade svansen mer i en hängande position (P<0,001). De beteenden som ansågs vara avkopplingsrelaterade, såsom dricka, äta och stryka kroppen mot inredningen, var inte signifikant högre hos lekgrisar. Sammanfattningsvis visade lekgrisarna vissa beteenden som indikerar förväntan i förväntansboxen, utförde alla tre typer av lek i lekarenan. Däremot visade lekgrisarna inte beteenden som ansågs indikera avkoppling i hemboxen

Stability Region of a Slotted Aloha Network with K-Exponential Backoff

Stability region of random access wireless networks is known for only simple network scenarios. The main problem in this respect is due to interaction among queues. When transmission probabilities during successive transmissions change, e.g., when exponential backoff mechanism is exploited, the interactions in the network are stimulated. In this paper, we derive the stability region of a buffered slotted Aloha network with K-exponential backoff mechanism, approximately, when a finite number of nodes exist. To this end, we propose a new approach in modeling the interaction among wireless nodes. In this approach, we model the network with inter-related quasi-birth-death (QBD) processes such that at each QBD corresponding to each node, a finite number of phases consider the status of the other nodes. Then, by exploiting the available theorems on stability of QBDs, we find the stability region. We show that exponential backoff mechanism is able to increase the area of the stability region of a simple slotted Aloha network with two nodes, more than 40\%. We also show that a slotted Aloha network with exponential backoff may perform very near to ideal scheduling. The accuracy of our modeling approach is verified by simulation in different conditions.Comment: 30 pages, 6 figure

On the Complexity of Chore Division

We study the proportional chore division problem where a protocol wants to divide an undesirable object, called chore, among $n$ different players. The goal is to find an allocation such that the cost of the chore assigned to each player be at most $1/n$ of the total cost. This problem is the dual variant of the cake cutting problem in which we want to allocate a desirable object. Edmonds and Pruhs showed that any protocol for the proportional cake cutting must use at least $\Omega(n \log n)$ queries in the worst case, however, finding a lower bound for the proportional chore division remained an interesting open problem. We show that chore division and cake cutting problems are closely related to each other and provide an $\Omega(n \log n)$ lower bound for chore division

Penerapan Model Pembelajaran Kooperatif Tipe STAD untuk Meningkatkan Hasil Belajar Siswa pada Materi Invers Matriks di Kelas XI IPA 1 MA Bilingual Batu

This research aims to determine the increment in student learning outcomes on inverse matrix material with Student Teams Achievement Division (STAD) type cooperative learning model. The research subjects were students of class XI IPA 1 MA Bilingual Batu in the 2018/2019 academic year, with a total of 33 students. This type of research is Action Research Classroom (PTK) with the implementation procedure referring to Kemmis and Mc Taggart, which is planning, acting, observing and reflection. This research was conducted in two cycles with the results in the first cycle the average value of the class was 75.4 and in the second cycle the average value of the class was 82.04. From the results obtained, it can be concluded that application of cooperative learning STAD could improve student learning outcomes in the inverse of matrix materials at class XI IPA MA Bilingual Batu

SeGAN: Segmenting and Generating the Invisible

Objects often occlude each other in scenes; Inferring their appearance beyond their visible parts plays an important role in scene understanding, depth estimation, object interaction and manipulation. In this paper, we study the challenging problem of completing the appearance of occluded objects. Doing so requires knowing which pixels to paint (segmenting the invisible parts of objects) and what color to paint them (generating the invisible parts). Our proposed novel solution, SeGAN, jointly optimizes for both segmentation and generation of the invisible parts of objects. Our experimental results show that: (a) SeGAN can learn to generate the appearance of the occluded parts of objects; (b) SeGAN outperforms state-of-the-art segmentation baselines for the invisible parts of objects; (c) trained on synthetic photo realistic images, SeGAN can reliably segment natural images; (d) by reasoning about occluder occludee relations, our method can infer depth layering.Comment: Accepted to CVPR18 as spotligh