On a queueing-inventory with reservation, cancellation, common life time and retrial

2015 ◽  
Vol 247 (1) ◽  
pp. 365-389 ◽  
Author(s):  
A. Krishnamoorthy ◽  
Dhanya Shajin ◽  
B. Lakshmy
Keyword(s):  
Life Time ◽  
Common Life ◽  
Common Life Time

A revisit to queueing-inventory system with reservation, cancellation and common life time

OPSEARCH ◽  
2016 ◽  
Vol 54 (2) ◽  
pp. 336-350 ◽  
Author(s):  
A. Krishnamoorthy ◽  
Binitha Benny ◽  
Dhanya Shajin
Keyword(s):  
Life Time ◽  
Inventory System ◽  
Common Life ◽  
Common Life Time

scholarly journals Analysis of an M/PH/1 Retrial Queueing-Inventory System with Level Dependent Retrial Rate

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zaiming Liu ◽  
Xuxiang Luo ◽  
Jinbiao Wu
Keyword(s):  
Life Time ◽  
Maximum Size ◽  
Inventory System ◽  
Phase Type Distribution ◽  
Steady State Probability ◽  
Numerical Illustration ◽  
Retrial Queueing ◽  
Common Life Time ◽  
The Stability ◽  
Number Of Customers

We analyze a queueing-inventory system which can model airline and railway reservation systems. An arriving customer to an idle server joins for service immediately with exactly one item from inventory at the moment of service completion if there are some on-hand inventory, or else he accesses to a buffer of varying size (the buffer capacity varies and equals to the number of the items in the inventory with maximum size S). When the buffer overflows, the customer joins an orbit of infinite capacity with probability p or is lost forever with probability 1−p. Arrivals form a Poisson process, and service time has phase type distribution. The time between any two successive retrials of the orbiting customer is exponentially distributed with parameter depending on the number of customers in the orbit. In addition, the items have a common life time with exponentially distributed. Cancellation of orders is possible before their expiry and intercancellation times are assumed to be exponentially distributed. The stability condition and steady-state probability vector have been studied by Neuts–Rao truncation method using the theory of Level Dependent Quasi-Birth-Death (LDQBD) processes. Several stationary performance measures are also computed. Furthermore, we provide numerical illustration of the system performance with variation in values of underlying parameters and analyze an optimization problem.

SEM and Auger microanalysis studies of Cu-Be dynode surfaces at each activation condition

1978 ◽  
Vol 36 (1) ◽  
pp. 524-525
Author(s):  
T. Koshikawa ◽  
Y. Fujii ◽  
E. Sugata ◽  
F. Kanematsu
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Life Time ◽  
Activation Process ◽  
Beam Diameter ◽  
Activation Temperature ◽  
Electron Multiplier ◽  
Activation Condition ◽  
Activation Conditions

The Cu-Be alloys are widely used as the electron multiplier dynodes after the adequate activation process. But the structures and compositions of the elements on the activated surfaces were not studied clearly. The Cu-Be alloys are heated in the oxygen atmosphere in the usual activation techniques. The activation conditions, e.g. temperature and O2 pressure, affect strongly the secondary electron yield and life time of dynodes.In the present paper, the activated Cu-Be dynode surfaces at each condition are investigated with Scanning Auger Microanalyzer (SAM) (primary beam diameter: 3μmϕ) and SEM. The commercial Cu-Be(2%) alloys were polished with Cr2O3 powder, rinsed in the distilled water and set in the vacuum furnance.Two typical activation condition, i.e. activation temperature 730°C and 810°C in 5x10-3 Torr O2 pressure were chosen since the formation mechanism of the BeO film on the Cu-Be alloys was guessed to be very different at each temperature from the results of the secondary electron emission measurements.

Negative Life Events Associated With Deliberate Self-Harm in an African Population in Uganda

Crisis ◽  
2005 ◽  
Vol 26 (1) ◽  
pp. 4-11 ◽  
Author(s):  
E. Kinyanda ◽  
H. Hjelmeland ◽  
S. Musisi
Keyword(s):  
Life Events ◽  
Negative Life Events ◽  
Life Time ◽  
Later Life ◽  
Dose Effect ◽  
Deliberate Self Harm ◽  
Time Period ◽  
Significant Difference ◽  
Self Harm ◽  
Suicide Interventions

Abstract. Negative life events associated with deliberate self-harm (DSH) were investigated in an African context in Uganda. Patients admitted at three general hospitals in Kampala, Uganda were interviewed using a Luganda version (predominant language in the study area) of the European Parasuicide Study Interview Schedule I. The results of the life events and histories module are reported in this paper. The categories of negative life events in childhood that were significantly associated with DSH included those related to parents, significant others, personal events, and the total negative life events load in childhood. For the later-life time period, the negative life events load in the partner category and the total negative life events in this time period were associated with DSH. In the last-year time period, the negative life events load related to personal events and the total number of negative life events in this time period were associated with DSH. A statistically significant difference between the cases and controls for the total number of negative life events reported over the entire lifetime of the respondents was also observed, which suggests a dose effect of negative life events on DSH. Gender differences were also observed among the cases. In conclusion, life events appear to be an important factor in DSH in this cultural environment. The implication of these results for treatment and the future development of suicide interventions in this country are discussed.

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