Planning Through Stochastic Local Search and Temporal Action Graphs in LPG

We present some techniques for planning in domains specified with the recent standard language PDDL2.1, supporting 'durative actions' and numerical quantities. These techniques are implemented in LPG, a domain-independent planner that took part in the 3rd International Planning Competition (IPC). LPG is an incremental, any time system producing multi-criteria quality plans. The core of the system is based on a stochastic local search method and on a graph-based representation called 'Temporal Action Graphs' (TA-graphs). This paper focuses on temporal planning, introducing TA-graphs and proposing some techniques to guide the search in LPG using this representation. The experimental results of the 3rd IPC, as well as further results presented in this paper, show that our techniques can be very effective. Often LPG outperforms all other fully-automated planners of the 3rd IPC in terms of speed to derive a solution, or quality of the solutions that can be produced

Plan stability: replanning versus plan repair

The ultimate objective in planning is to construct plans for execution. However, when a plan is executed in a real environment it can encounter differences between the expected and actual context of execution. These differences can manifest as divergences between the expected and observed states of the world, or as a change in the goals to be achieved by the plan. In both cases, the old plan must be replaced with a new one. In replacing the plan an important consideration is plan stability. We compare two alternative strategies for achieving the {em stable} repair of a plan: one is simply to replan from scratch and the other is to adapt the existing plan to the new context. We present arguments to support the claim that plan stability is a valuable property. We then propose an implementation, based on LPG, of a plan repair strategy that adapts a plan to its new context. We demonstrate empirically that our plan repair strategy achieves more stability than replanning and can produce repaired plans more efficiently than replanning

Reformulation in planning

Reformulation of a problem is intended to make the problem more amenable to efficient solution. This is equally true in the special case of reformulating a planning problem. This paper considers various ways in which reformulation can be exploited in planning

Exploiting Macro-actions and Predicting Plan Length in Planning as Satisfiability

The use of automatically learned knowledge for a planning domain can significantly improve the performance of a generic planner when solving a problem in this domain. In this work, we focus on the well-known SAT-based approach to planning and investigate two types of learned knowledge that have not been studied in this planning framework before: macro-actions and planning horizon. Macro-actions are sequences of actions that typically occur in the solution plans, while a planning horizon of a problem is the length of a (possibly optimal) plan solving it. We propose a method that uses a machine learning tool for building a predictive model of the optimal planning horizon, and variants of the well-known planner SatPlan and solver MiniSat that can exploit macro actions and learned planning horizons to improve their performance. An experimental analysis illustrates the effectiveness of the proposed techniques

Static and Dynamic Portfolio Methods for Optimal Planning: An Empirical Analysis

Combining the complementary strengths of several algorithms through portfolio approaches has been demonstrated to be effective in solving a wide range of AI problems. Notably, portfolio techniques have been prominently applied to suboptimal (satisficing) AI planning. Here, we consider the construction of sequential planner portfolios for domainindependent optimal planning. Specifically, we introduce four techniques (three of which are dynamic) for per-instance planner schedule generation using problem instance features, and investigate the usefulness of a range of static and dynamic techniques for combining planners. Our extensive empirical analysis demonstrates the benefits of using static and dynamic sequential portfolios for optimal planning, and provides insights on the most suitable conditions for their fruitful exploitation

Cerebrospinal fluid analysis for HIV replication and biomarkers of immune activation and neurodegeneration in long-term atazanavir/ritonavir monotherapy treated patients

Background: Cerebrospinal fluid (CSF) viral escape is a concern in ritonavir-boosted protease inhibitors monotherapy. The aim was to assess HIV-RNA, biomarkers of immune activation and neurodegeneration, and atazanavir concentrations in CSF of patients on successful long-term atazanavir/ritonavir (ATV/r) monotherapy. Methods: This is a substudy of the multicentric, randomized, open-label, noninferiority trial monotherapy once a day with atazanavir/ritonavir (NCT01511809), comparing the ongoing ATV/r along with 2 nucleoside retrotranscriptase inhibitors (NRTIs) regimen to a simplified ATV/r monotherapy. Patients with plasma HIV-RNA < 50 copies/mL after at least 96 study weeks were eligible. We assessed HIV-RNA, soluble (s)CD14, sCD163, CCL2, CXCL10, interleukin-6, and YKL40 by enzyme-linked immunosorbent assay; neopterin, tryptophan, kynurenine, and neurofilament by immunoassays; and ATV concentrations by liquid chromatography–mass spectrometry in paired plasma and CSF samples. Variables were compared with Wilcoxon rank-sum or Fisher exact test, as appropriate. Results: HIV-RNA was detected in the CSF of 1/11 patients on ATV/r monotherapy (114 copies/mL), without neurological symptoms, who was successfully reintensified with his previous 2NRTIs, and in none of the 12 patients on ATV/r + 2NRTIs. CSF biomarkers and ATV concentrations did not differ between the 2 arms. Conclusions: CSF escape was uncommon in patients on long-term ATV/r monotherapy and was controlled with reintensification

A

Abstract:&nbsp; Studies show that patients with type 2 diabetes (DM2) have a higher risk of developing some type of cancer. Objective:&nbsp;to analyze the incidence and association between DM2 and cancer in patients from the “San Ricardo Pampuri” health center in Villa Carlos Paz. A retrospective observational study was carried out analyzing the medical records of 42,948 patients (years 2000-2018), 17,109 (39.8%) had DM2 and 332 had cancer (186M and 146H). The data analyzed were age, sex, type of cancer and suffering from DM2. Incidence ratios between sexes (RS = incidence in Men / incidence in Women) were calculated for some types of cancer. The work has ethical approval and corresponding confidentiality. Data were statistically analyzed with Infostat. Average age was 72 (DS 11) years for men and 68.5 (DS 12) for women (56% of the patients). 162 patients who developed cancer had DM2 (93M and 69H). In women with DM2 the incidences were: breast (51.6%), endometrium (7.5%), colon, pancreas and cervix (all with 6.5%). In women without DM2: breast (41.1%), colon (14.4%), cervix (7.8%), ovary and thyroid (both with 5.6%). In men with DM2 the incidences: prostate (27.9%), colon (19.1%), pancreas (8.8%), kidney (7.4%), Non-Hodgkin\u27s Lymphoma and bladder (both with 5.9 %). In those without DM2 they were: prostate (40%), colon (18.8%), bladder (12.5%) and melanoma (5%). The highest incidence rates between sexes (SR) for patients with DM2 were: lung (4.1), colon (3), Non-Hodgkin\u27s Lymphoma (2.7), kidney (2.3) and myeloma (2); in patients without DM2 they were bladder (3.8) and leukemia (2.3). It was observed that diabetic patients have a higher risk for pancreatic cancer (OR = 6.96; p = 0.01) and kidney (OR = 4.96; p = 0.01). Men showed a slightly increased risk for: colon (OR = 0.49; p = 0.02), bladder (OR = 0.16; p = 0.05) and kidney (OR = 0.29; p = 0 , 05). It was observed that patients without DM2 showed a slightly elevated risk for bladder cancer (OR = 0.33; p = 0.05) and melanoma (OR = 0.13; p = 0.05). Conclusions: Positive correlations were observed between cancer and age, for some tumors it could also be established with sex and DM2. Patients with DM2 showed an increased risk for pancreatic and kidney cancer and a small decrease in risk for bladder and melanoma.Resumen:&nbsp; Numerosos estudios demuestran que pacientes con diabetes tipo 2 (DM2) tienen mayor riesgo de desarrollar algún tipo&nbsp;de cáncer. Objetivo del estudio:&nbsp;analizar la incidencia y asociación entre DM2 y cáncer en pacientes del centro de salud “San Ricardo Pampuri” de Villa Carlos Paz.&nbsp; Se realizó un estudio observacional retrospectivo analizando historias clínicas de 42948 pacientes &nbsp;(años 2000-2018), 17109 (39,8%) padecían DM2 y 332 &nbsp;presentaron &nbsp;cáncer (186M y 146H). Los datos analizados fueron edad, sexo, tipo de cáncer y padecer DM2. Se calcularon ratios de incidencia entre sexos (RS=incidencia Hombres/incidencia Mujeres) para algunos tipos de cáncer.&nbsp; El trabajo cuenta con&nbsp; aprobación ética y confidencialidad correspondiente. Se analizaron los datos estadísticamente con Infostat. Edad promedio fue 72(DS 11)&nbsp;años hombres y 68,5 (DS 12) mujeres (56% de los pacientes). 162 pacientes que desarrollaron cáncer tenían DM2 (93M y 69H). En mujeres con DM2&nbsp; incidencias fueron: mama (51,6%), endometrio (7,5%), colon, páncreas y cuello de útero (todos con 6,5%). En mujeres sin DM2: mama (41,1%), colon (14,4%), cuello de útero (7,8%) ovario y tiroides (ambos con 5,6%). En hombres con DM2 las incidencias: próstata (27,9%), colon (19,1%), páncreas (8,8%), riñón (7,4%), Linfoma No Hodgkin y vejiga (ambos con 5,9%). En aquellos sin DM2 fueron: próstata (40%), colon (18,8%), vejiga (12,5%) y melanoma (5%). Las ratios de incidencia entre sexos (RS) más altos para pacientes con DM2 fueron: pulmón (4,1), colon (3), Linfoma No Hodgkin (2,7), riñón (2,3) y mieloma (2); en pacientes sin DM2 fueron vejiga (3,8) y leucemia (2,3). Se observó que pacientes diabéticos tienen un riesgo mayor para cáncer de páncreas (OR=6,96; p=0,01) y riñón (OR=4,96; p=0,01). Los hombres mostraron un riesgo levemente aumentado para: colon (OR=0,49; p=0,02), vejiga (OR=0,16; p=0,05) y riñón (OR=0,29; p=0,05). Se observó que pacientes sin DM2 mostraron un riesgo ligeramente elevado para cáncer de vejiga (OR=0,33; p=0,05) y melanoma (OR=0,13; p=0,05).&nbsp; Conclusiones:&nbsp; Se observaron correlaciones positivas entre cáncer y edad, para algunos tumores también se pudieron establecer con sexo y DM2.&nbsp; Los pacientes con DM2 mostraron un riesgo mayor para cáncer de páncreas y riñón y una pequeña disminución del riesgo para vejiga y melanoma.