Comparison of Pre-processing Methods and Various Machine Learning Models for Survival Analysis on Cancer Data

Colorectal cancer and cancers in the head and neck region still pose a big problem in medicine and in the healthcare sector. In 2021 alone 11 121 deaths could be accounted for due to various cancers, with colorectal and head and neck cancer being among the more common types. In today's digital age, hospitals and researchers are collecting more data than ever before. Many studies have patients where the follow-up or study has ended before an event of interest occurs. Instead of discarding those patients from observed data when applying machine learning methods and subsequently losing valuable information, survival analysis can be applied. Survival analysis utilizes the information from the censoring variable that tells whether or not the event of interest has taken place before the study has ended. In this thesis several pre-processing techniques were utilized, such as removal of outliers, feature distribution transformations and feature selection techniques. These techniques were applied together with multiple machine learning algorithms from the scikit-learn and scikit-survival library. The survival algorithms used were Regularized Cox model with elastic net (Coxnet), random survival forest, tree based gradient boosting and gradient boosting with partial least squares as base learner. These algortihms take into account the information from the censoring variable in addition to the survival time. Other machine learning algorithms used were linear regression, ridge regression and Partial least squares regression (PLSR), where the last three algorithms only use the survival time as the target and do not account for the censoring variable. Two datasets were used in this thesis, one with patients diagnosed with colorectal cancer, and the second with patients diagnosed with various head and neck cancers. Furthermore, two experiments were carried out separately and validated by the use of repeated stratified k-fold cross validation. In the first experiment the models were fitted to different feature transformations of the datasets in combination with feature selection techniques. The second experiment involved hyperparameter tuning for the survival models. There was little difference in performance between the transformations, with no improvement on the head and neck dataset, however for the high dimensional colorectal cancer dataset, powertransformation led to a very small increase of 0.02 in the concordance index. The feature selection techniques did improve the performance of four of the models, which were Linear Regression, Ridge Regression, PLSR and Coxnet. For the more advanced survival models which were Gradient Boosted and Random Survival Forest, the feature selection did in general not improve metrics, as they might have benefited from greedily selecting features and updating feature weights on their own. The best model in the first experiment for OxyTarget was Random Forest with powertransform applied before, and all features available. This resulted in a concordance index of 0.83. For the head and neck dataset both Component Wise gradient boosting, Coxnet and PLSR were able to achieve the highest concordance index with 0.77, with Coxnet able to achieve that score across all three transformations. In the second experiment, all the survival models were tuned for different hyperparameters to see if the various metrics would improve. A small performance increase could be seen for several models. However, for the dataset with colorectal cancer, a Coxnet model tuned with a low regularization strength and low l1\_ratio penalty yielded a large increase in the concordance index and resulted in the best model with a score of 0.827. For the head and neck dataset, parameter tuning the Random Survival Forest algorithm for min\_weight\_fraction\_leaf and max\_depth resulted in the best model, and a concordance of 0.787 was achieved. The research and the framework created to conduct the aforementioned experiments show that more promising ranking results while maintaining robust models can be achieved through the use of pre-processing techniques and through the utilization of all data using repeated stratified k-fold cross validation. However, as the research conducted shows, there is no universal best algorithm or method to conduct survival analysis for cancer data, as it depends on the data

Local self-government in a crisis caused by the Covid-19 pandemic: the case of Serbia

This research examined whether there is an elaborate system of protocols, protection, and prevention in place at the local self-government level in the event of a crisis caused by an epidemic or pandemic. The core idea of this paper was to evaluate the protocol's effectiveness at the local self-government. Analysis was conducted using responses of 16 local self-government authorities. During a crisis caused by an epidemic/a pandemic of infectious illnesses, surveys were done as a cross-section documenting and detecting the current state of local self-government functioning. Methods used in the study are defining the objectives of the research, conceptualization, analysis of legal regulations, economic analysis, and decomposition of the problem. Key results and arguments of this paper expanded existing research thus there are only certain empirical data from areas that have been affected by the infectious disease caused by the epidemic/pandemic. Data was collected, processed, and systematized to serve in model formulation. As a brief conclusion, this study suggested protocol effectiveness at the local self-government level representing the idea that emergency and crisis management should be organized to preserve the health and livelihood of the population in the area affected by the pandemic of infectious diseases and thus enable the functioning of economic activities and society as a whole

The Application of Bass Diffusion Model in Forecasting Telecommunication Services Users in Military Assistance to Civilian Authorities

This paper analyses the application of Bass’s diffusion model in forecasting the number of telecommunication services users in the event of natural disasters. Citizens’ behaviour has been modelled in the case of an emergency situation caused by an earthquake with high magnitude. We analysed the area of an administrative district in the south-west part of the Republic of Serbia which includes two cities and three municipalities. To control the consequences of natural disasters, a unit of the Army of Serbia with the required number of radio transceivers for establishing communication between the vulnerable population and rescuers with command staff at the observed territory has been dimensioned. Special emphasis is given to the provision of telecommunication support in the military assistance in a relief operation with civil authorities.Defence Science Journal, Vol. 65, No. 2, March 2015, pp.144-149, DOI:http://dx.doi.org/10.14429/dsj.65.602

Policy of raising the capacity of local self-governments for management of emergencies

Local self-governments (LSGs) cannot effectively manage emergencies. To overcome this problem, it is necessary to find action policies that would facilitate the increase of capacities of LSGs in such situations. The starting point for defining the policy was collecting data on the current abilities and capacities of LSGs in AP Vojvodina. The research covered 40% of the total number of LSGs and more than 64% of the population in the AP of Vojvodina. A combined open-ended survey questionnaire was constructed for data collection. The data was collected in field conditions through online procedures, direct sending of written surveys, and direct discussion of project implementation leaders. The statistical analysis of data identified that the legal aspect of LSGs and emergencies was not harmonized with other institutional documents at the level of LSGs. Most LSGs had serious difficulties in managing emergencies, especially civil protection. The platform is envisaged to facilitate raising the prevention capacity of LSGs by integrating all relevant information to provide early warnings and indications for implementing corresponding organizational, technical, and economic measures to deal with emergencies

Sorafenib dose escalation is not uniformly associated with blood pressure elevations in normotensive patients with advanced malignancies.

Hypertension after treatment with vascular endothelial growth factor (VEGF) receptor inhibitors is associated with superior treatment outcomes for advanced cancer patients. To determine whether increased sorafenib doses cause incremental increases in blood pressure (BP), we measured 12-h ambulatory BP in 41 normotensive advanced solid tumor patients in a randomized dose-escalation study. After 7 days' treatment (400 mg b.i.d.), mean diastolic BP (DBP) increased in both study groups. After dose escalation, group A (400 mg t.i.d.) had marginally significant further increase in 12-h mean DBP (P = 0.053), but group B (600 mg b.i.d.) did not achieve statistically significant increases (P = 0.25). Within groups, individuals varied in BP response to sorafenib dose escalation, but these differences did not correlate with changes in steady-state plasma sorafenib concentrations. These findings in normotensive patients suggest BP is a complex pharmacodynamic biomarker of VEGF inhibition. Patients have intrinsic differences in sensitivity to sorafenib's BP-elevating effects

The effects of mineral adsorbents added to broilers diet on breast meat quality

The aim of these investigations was to determine the influence of mineral adsorbents Minazel and Minazel Plus added into broiler diet, on the carcass quality and nutritional, technological and sensory properties of breast meat. The examination was done on Cobb 500 provenience divided into 4 groups: control group C (fed without addition of mineral adsorbent), experimental group E I (0.5% of Minazel), experimental group E II (0.2% of Minazel Plus), experimental group E III (0.3% of Minazel Plus). The results showed that the broilers fed with the addition of mineral adsorbents, had a higher (P < 0.01) mass of chilled carcass ready to grill and breast mass, than the broilers of the control group. Based on the parameters and criteria for defining the quality of chicken breast meat (pHu and L*) it can be concluded that meat of all groups had in average normal quality. According to the results of sensory analyzed roasted breast meat, meat of experimental groups had preferable smell and tenderness

Performance Analysis of One Model of Communication and Information System in Military Operation

This paper presents a model of communication and information system in military operations. Here OPNET MODELER simulation package is applied because it is suitable for network modelling, topology and capacity planning. Simulation of different types of IP traffic and monitor their performance to optimise the functionality of network elements, management performance network applications, and as well as in research and development of new network technologies. Application of the method of mass service are determined by the capacity needed for voice transmission on the links in the model and using the OPNET MODELER simulation program are analysed performance modeled communication information system in data transmission. The results of the simulation are presented through target the service settings: workload links communication and information system, e-mail download response time, http page download response time and packet loss in data transfer. The aim of the research has shown that modeled communication information system with defined elements (nodes), the capacity of links (according to the specification of telecommunication devices) and defined traffic can respond to the requirements of command forces in the military operation in terms of telecommunication service. The results of the analysed service target parameters show that modeled communication and information system provides an efficient flow of information and the tra nsfer of voice and IP data for the needs of command and control in military operations

Self-care in patients with heart failure

Hjärtsvikt tillhör en av Sveriges stora folksjukdomar och är den vanligaste inläggningsorsaken på sjukhus bland personer över 65 år. Hjärtsvikt är ett tillstånd där hjärtats pumpförmåga inte kan försörja kroppens vävnader med tillräcklig mängd blod. Patienter som lider av hjärtsvikt går en förändrad livsstil till mötes. Därmed behöver dessa patienter mycket information och kunskap för att öka delaktigheten och kunna planera och genomföra egenvård. Sjuksköterskan måste därför uppmärksamma och undersöka på vilket sätt och med vilka faktorer detta kan uppnås. Syftet med den här litteraturöversikten var att belysa olika faktorer som påverkar delaktighet och förmågan till egenvård hos patienter med hjärtsvikt. Resultatet baserades på 13 vetenskapliga artiklar från databaserna PubMed och CINAHL. Sex artiklar hade kvalitativ metod, sex artiklar hade kvantitativ metod och en artikel hade både kvalitativ och kvantitativ metod. Kvalitetsgranskningen av artiklarna gjordes enligt en granskningsmall av Willman, Stoltz och Bahtsevani (2011). Resultatet visade att följande faktorer skapar möjligheter för att patienter med hjärtsvikt ska kunna uppnå tillfredsställande delaktighet och förmåga till egenvård: patientutbildning till den unika individen, vikten av rätt tidpunkt för information och utbildning, vikten av att integrera patient och få denne delaktig samt god pedagogik vid informationsöverföring. Följande faktorer påverkar förutsättningarna för patientens egenvård och delaktighet negativt: bristande förståelse kring sjukdomen, osäkerhet i den nyuppkomna situationen, okunskap, känsla av utanförskap och objektifiering. Från vår litteraturöversikt drar vi slutsatsen att det finns faktorer, i den moderna omvårdnaden av hjärtsvikts patienter, som både stimulerar och försvårar patienters delaktighet och egenvård. Mera omfattande forskning efterfrågas vad avser specifika förhållningssätt och vad sjuksköterskan kan bidra med för att få hjärtsviktspatienter mera engagerade i sin vård