An improved method for the effect estimation of the intermediate event on the outcome based on the susceptible pre-identification

Background In follow-up studies, the occurrence of the intermediate event may influence the risk of the outcome of interest. Existing methods estimate the effect of the intermediate event by including a time-varying covariate in the outcome model. However, the insusceptible fraction to the intermediate event in the study population has not been considered in the literature, leading to effect estimation bias due to the inaccurate dataset. Methods In this paper, we propose a new effect estimation method, in which the susceptible subpopulation is identified firstly so that the estimation could be conducted in the right population. Then, the effect is estimated via the extended Cox regression and landmark methods in the identified susceptible subpopulation. For susceptibility identification, patients with observed intermediate event time are classified as susceptible. Based on the mixture cure model fitted the incidence and time of the intermediate event, the susceptibility of the patient with censored intermediate event time is predicted by the residual intermediate event time imputation. The effect estimation performance of the new method was investigated in various scenarios via Monte-Carlo simulations with the performance of existing methods serving as the comparison. The application of the proposed method to mycosis fungoides data has been reported as an example. Results The simulation results show that the estimation bias of the proposed method is smaller than that of the existing methods, especially in the case of a large insusceptible fraction. The results hold for small sample sizes. Besides, the estimation bias of the new method decreases with the increase of the covariates, especially continuous covariates, in the mixture cure model. The heterogeneity of the effect of covariates on the outcome in the insusceptible and susceptible subpopulation, as well as the landmark time, does not affect the estimation performance of the new method. Conclusions Based on the pre-identification of the susceptible, the proposed new method could improve the effect estimation accuracy of the intermediate event on the outcome when there is an insusceptible fraction to the intermediate event in the study population.

Strategic management approach for port state control

Purpose The purpose of this study is to fill the gap and apply a fault tree analysis (FTA) in detention lists of Black Sea Region published port state reports from 2005 to 2016. The study analyzes valid records of 2,653 detained ships with 6,374 deficiencies based on a strategic management approach. This paper sets up FTA technique to assess the detention probability of a random ship which calls the Black Sea Region with the help of detention lists published within subject years. Design/methodology/approach This paper is not published elsewhere, and it is based on an original work, which figures out detention probability of a regular ship at Black Sea Region port state control from published lists of Black Sea Memorandum of Understanding (MoU). By utilizing these detention lists, a generic fault tree diagram is drawn. Those probabilities could be used strategically with the most seen deficiencies in the region which all could guide the users, rule makers and the controllers of the maritime system. Findings FTA has conducted based on the data which was collected from website of BS MoU detention lists that published from 2005 to 2016. Those lists have been published on monthly basis from 2011 to 2016 and on quarterly basis from 2005 to 2010. Proper detention records have been included into the research, whereas some missing records were excluded. Subject lists have been harmonized and rearranged according to Black Sea MoU Detention Codes which was published on October 2017 at Black Sea MoU’s website. According to BS MoU Annual Reports, 58,620 ships were inspected from 2005 to 2016 as seen in Table 1. Those ships were inspected by each member country’s PSOs in the light and guidance of predefined selection criteria of the region. Detention frequency of inspected ships detected as 0.103116 which explains any ship that called any port in the Black Sea Region could be 10% detained after inspected by PSO. Also, each intermediate event-calculated frequency enlightens the probabilities of nonconformities of ships. Although those deficiencies show structural safety and security nonconformities, those probabilities also prove us that management side of the ships are not enough to manage and apply a safety culture. By the light of that, ship owners/managers could see the general nonconformities according to regional records and could manage their fleet and each ship as per those necessities. Research limitations/implications In the light of the above analysis, the future research on this subject could be studied on other regions which might enable a benchmark opportunity to users. Also, insurance underwriters have their own reports and publications that could clarify different points of view for merchant mariners and regulators. In this research, FTA is used as a main method to figure out the root causes of the detentions. For future researches, different qualitative and quantitative methods could be used under the direction of subjects. Practical implications Detention frequency of inspected ships detected as 0.103116 which explains any ship that called any port in the Black Sea Region could be 10% detained after inspected by PSO. Also, each intermediate event-calculated frequency enlightens the probabilities of nonconformities of ships. Although those deficiencies show structural safety and security nonconformities, those probabilities also prove us that management side of the ships are not enough to manage and apply safety culture. By the light of that, ship owners/managers could see the general nonconformities according to regional records and could manage their fleet and each ship as per those necessities. Social implications With the nature of carriage, shipping business carry out its essential economic attendance in world trade system via inclusion in national and international transportation. As a catalyst in international trade, shipping itself enables time, place and economic benefits to users (Bosneagu, Coca and Sorescu, 2015). Social and institutional pressures generate shipping industry as one of the most regulated global industries which creates high complexity. Industry evolved to multi-directional structure ranges from international conventions (IMO and ILO) to “supra-national interferences” (EU directives), to regional guidance (MoUs) to national laws (flag states). Ship operators endeavor to adopt/fit its industry environment where rules are obvious. With adaptation of industrial environment, ship operators are able to create an important core competency. Originality/value This study enlightens the most recorded deficiencies and analyzed them with the help of fault three method. These calculated frequencies/probabilities show the most seen nonconformities and the root causes of detentions in the Black Sea Region in which those results will be benefited strategically that enables a holistic point of view that guide the owners/managers, charterers/sellers/shippers, classification societies, marine insurance underwriters, ship investors, third parties, rule makers and the controllers of the system to apply safety culture.

A new non-linear framework for localization of acoustic sources

Source localization is the process of assigning spatial metadata to a set of unlabeled time of arrival for acoustic signals that may be interlaced with extreme outliers caused by detection and material-induced errors. Exploiting the fact that location error is attributed to high residuals, a new framework for non-linear source localization is proposed in this article. The detected time of arrival was employed to calculate the intermediate source and event time. The framework then quarantines sensors with high residual based on the intermediate event time and relative distance from the intermediate source. Then, the time of arrivals for quarantined sensors were reviewed and adjusted. Finally, with new arrival time, the framework iteratively optimizes the spatial location and event time, along with the updating of velocity field through a feedback loop. The new framework was used to localize acoustic emission sources with extreme outliers in an anisotropic medium. The results indicate that the proposed framework can accurately quarantine the bad sensor and localize sources with an accuracy better than existing source localization methods. Finally, the framework was employed to study the progressive damage in a steel fiber–reinforced beam under four-point bending. The source localization result is consistent with that from visual inspection of the member at failure.

Working towards a better understanding of Helicobacter pylori-related gastric cancer’s biology

<p>Gastric cancer is a significant cause of cancer-related mortality and morbidity. In terms of disease etiology, it ranks as the fourth and fifth most common contributor of male and female cancer-related death, respectively [1]. A marked geographical variability has been observed for gastric cancer incidence, with the majority of cases reported in Eastern Europe, South America, and Asia [2]. This has been ascribed to environmental (<em>e.g.</em>, <em>H. pylori</em> infection), dietary, as well as genetic factors [3]. <em>H. pylori</em> is considered as a definite carcinogen by the International Agency for Research on Cancer, and intes-tinal metaplasia has been suggested as the intermediate event in the development of <em>H. pylori</em>-related gastric cancer [4]. However, the molecular mechanism of this event needs to be further elucidated. In this issue of <em>AMOR</em>, a report from Ukraine’s Vinnitsa National Pigorov Memorial Medical University by Sergii Vernygorodskyi attempts to improve our current understanding of the molecular mechanism associated with <em>H. pylori</em>-related gastric carcinogenesis [5]. The investigator found that the activation of CDX2, along with the simultaneous inactivation and a decreased number of genes (<em>e.g.</em>, <em>SHH</em>, <em>SOX2</em>, and <em>RUNX3</em>) responsible for gastric differentiation, is a probable cause that leads to the ap-pearance of intestinal metaplasia. Therefore, this study serves as an important catalyst to promote further research on the molecular mechanism and programming of gastric cancer cells, in hope of gaining new knowledge in the prevention and treatment of gastric cancer.</p>

PENGEMBANGAN RISK ASSESSMENT DALAM EVALUASI MANAJEMEN PENANGGULANGAN KEBAKARAN MELALUI FAULT TREE ANALYSIS

Fault tree analysis adalah suatu penilaian risiko yang mampu mengidentifikasi potensi bahaya secara spesifik, fokus, rinci pada satu kejadian yang tidak diinginkan, dan mengetahui penyebab kejadian tersebut beserta angka probabilitasnya. Tercatat mulai tanggal 1 Januari – 30 April 2014 terjadi kebakaran sebanyak 10 kali di divisi spinning PT. Apac Inti Corpora dengan kasus tertinggi di unit spinning V (50% kejadian).Tujuan penelitian ini adalah mengetahui faktor penyebab kebakaran, mengembangkan penilaian risiko, dan mengetahui gambaran umum sistem manajemen penanggulangan kebakaran di unit spinning V PT. AIC. Desain penelitian ini adalah kualitatif eksplanatoris. Hasil pengembangan bagan fault tree analysis didapatkan 41 basic event, 24 intermediate event, 1 conditioning event, dan 1 undeveloped event yang secara matematis melalui persamaan aljabar boolean akan menghasilkan 35 single minimum cut sets dan 5 double component cut sets, dengan perhitungan angka probabilitas sebesar 0,3552. Hasil kesesuaian sistem manajemen penanggulangan kebakaran didapatkan 76 poin dari 81 poin standar regulasi yang berlaku di Indonesia. Simpulan penelitian ini adalah kemungkinan terjadinya kebakaran di spinning V sebesar 35,52%. Saran dari penelitian ini adalah dilakukannya evaluasi terhadap kegagalan deteksi dini dan kegagalan teknis. Fault tree analysis has advantages in identifying potential hazards in specifics, focus, detail on a potential undesirable event that called top event, and was able to find out the causes with the value of probability. Recorded at January 1th – April 30th, 2014, there had been 10 cases of fires in the spinning PT. Apac Inti Corpora with the highest cases at spinning V (50% event). The purpose of this research was find out the cause of fires, develop a risk assessment, and learn an overview of fires countermeasures management system in spinning V. This research was a qualitative – explanatory design. Result of development fault tree analysis brings about 41 basic event, 24 intermediate event, 1 conditioning event, dan 1 undeveloped event by boolean algebra, mathematically generates 35 single minimum cut sets and 5 double component cut sets, with the value of probability is 0,3552. Whereas the countermeasure of fire management system conformity obtained 76 points is according from 81 points of regulatory standards in Indonesia. Summary, spinning unit V had the possibility of going fires is 35,52%. Advice, conducted evaluation of failure from early detection and technical failures in the production process.