229,489 research outputs found
Redesigning A Trolley for The Stairs Building Based on Material Aspect
In Bandung, some buildings have three levels or more with no escalator and elevator for their daily needs in moving goods. One example is the Telkom University dormitory. As a resident of a building, problems are often found unconsciously and that has not been found a clear solution, for example when moving goods from the ground to the top level. The goods are referred to as suitcases, gallons, dispensers, large bags, etc. Some people will call the services of a porter or friend to help them transport goods. Because of that, a clear solution must be made for goods mobilization activities to be more effective and efficient, therefore, transportation equipment such as trolleys with good material and it can accommodate the load of goods that are usually moved in buildings without elevators is a solution for this problem.
Keywords Stairs trolley, Material, Dormitory, Bandun
Spontaneous Analogy by Piggybacking on a Perceptual System
Most computational models of analogy assume they are given a delineated
source domain and often a specified target domain. These systems do not address
how analogs can be isolated from large domains and spontaneously retrieved from
long-term memory, a process we call spontaneous analogy. We present a system
that represents relational structures as feature bags. Using this
representation, our system leverages perceptual algorithms to automatically
create an ontology of relational structures and to efficiently retrieve analogs
for new relational structures from long-term memory. We provide a demonstration
of our approach that takes a set of unsegmented stories, constructs an ontology
of analogical schemas (corresponding to plot devices), and uses this ontology
to efficiently find analogs within new stories, yielding significant
time-savings over linear analog retrieval at a small accuracy cost.Comment: Proceedings of the 35th Meeting of the Cognitive Science Society,
201
Modular Termination Verification
We propose an approach for the modular specification and verification of total correctness properties of object-oriented programs. We start from an existing program logic for partial correctness based on separation logic and abstract predicate families. We extend it with call permissions qualified by an arbitrary ordinal number, and we define a specification style that properly hides implementation details, based on the ideas of using methods and bags of methods as ordinals, and exposing the bag of methods reachable from an object as an abstract predicate argument. These enable each method to abstractly request permission to call all methods reachable by it any finite number of times, and to delegate similar permissions to its callees. We illustrate the approach with several examples
An EPTAS for machine scheduling with bag-constraints
Machine scheduling is a fundamental optimization problem in computer science.
The task of scheduling a set of jobs on a given number of machines and
minimizing the makespan is well studied and among other results, we know that
EPTAS's for machine scheduling on identical machines exist. Das and Wiese
initiated the research on a generalization of makespan minimization, that
includes so called bag-constraints. In this variation of machine scheduling the
given set of jobs is partitioned into subsets, so called bags. Given this
partition a schedule is only considered feasible when on any machine there is
at most one job from each bag.
Das and Wiese showed that this variant of machine scheduling admits a PTAS.
We will improve on this result by giving the first EPTAS for the machine
scheduling problem with bag-constraints. We achieve this result by using new
insights on this problem and restrictions given by the bag-constraints. We show
that, to gain an approximate solution, we can relax the bag-constraints and
ignore some of the restrictions. Our EPTAS uses a new instance transformation
that will allow us to schedule large and small jobs independently of each other
for a majority of bags. We also show that it is sufficient to respect the
bag-constraint only among a constant number of bags, when scheduling large
jobs. With these observations our algorithm will allow for some conflicts when
computing a schedule and we show how to repair the schedule in polynomial-time
by swapping certain jobs around
A contraction-recursive algorithm for treewidth
Let tw(G) denote the treewidth of graph G. Given a graph G and a positive
integer k such that tw(G) <= k + 1, we are to decide if tw(G) <= k. We give a
certifying algorithm RTW ("R" for recursive) for this task: it returns one or
more tree-decompositions of G of width <= k if the answer is YES and a minimal
contraction H of G such that tw(H) > k otherwise.
RTW uses a heuristic variant of Tamaki's PID algorithm for treewidth
(ESA2017), which we call HPID. RTW, given G and k, interleaves the execution of
HPID with recursive calls on G /e for edges e of G, where G / e denotes the
graph obtained from G by contracting edge e. If we find that tw(G / e) > k,
then we have tw(G) > k with the same certificate. If we find that tw(G / e) <=
k, we "uncontract" the bags of the certifying tree-decompositions of G / e into
bags of G and feed them to HPID to help progress. If the question is not
resolved after the recursive calls are made for all edges, we finish HPID in an
exhaustive mode. If it turns out that tw(G) > k, then G is a certificate for
tw(G') > k for every G' of which G is a contraction, because we have found tw(G
/ e) <= k for every edge e of G. This final round of HPID guarantees the
correctness of the algorithm, while its practical efficiency derives from our
methods of "uncontracting" bags of tree-decompositions of G / e to useful bags
of G, as well as of exploiting those bags in HPID.
Experiments show that our algorithm drastically extends the scope of
practically solvable instances. In particular, when applied to the 100
instances in the PACE 2017 bonus set, the number of instances solved by our
implementation on a typical laptop, with the timeout of 100, 1000, and 10000
seconds per instance, are 72, 92, and 98 respectively, while these numbers are
11, 38, and 68 for Tamaki's PID solver and 65, 82, and 85 for his new solver
(SEA 2022).Comment: 17 pages, 2 figures, submitted IPEC 202
Mayha
Me: Where does my nickname come from?
My mom: Well, your nickname is Mayha, and, that all originated one Christmas when my grandma, who was your great-grandmother, was writing all of the grandchildren, great- grandchildren’s names on paper bags, um...which was basically the gift wrap for Christmas presents that year. And when we got your bag, it said M-a-y-h-a [spelled out], where your name is actually pronounced – spelled, M-a-y-a-h [spelled out]. So instead of Mayah she had spelled Mayha, and we just that it was so funny that we continued to call you Mayha ever since, and, I don’t know it’s probably been over ten years now and we still call you Mayha, because of your great-grandmother spelling your name wrong on your Christmas present
Fixed-parameter tractable canonization and isomorphism test for graphs of bounded treewidth
We give a fixed-parameter tractable algorithm that, given a parameter and
two graphs , either concludes that one of these graphs has treewidth
at least , or determines whether and are isomorphic. The running
time of the algorithm on an -vertex graph is ,
and this is the first fixed-parameter algorithm for Graph Isomorphism
parameterized by treewidth.
Our algorithm in fact solves the more general canonization problem. We namely
design a procedure working in time that, for a
given graph on vertices, either concludes that the treewidth of is
at least , or: * finds in an isomorphic-invariant way a graph
that is isomorphic to ; * finds an isomorphism-invariant
construction term --- an algebraic expression that encodes together with a
tree decomposition of of width .
Hence, the isomorphism test reduces to verifying whether the computed
isomorphic copies or the construction terms for and are equal.Comment: Full version of a paper presented at FOCS 201
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