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We propose a new flexible class called the Marshall-Olkin odd Burr III family for generating continuous distributions and derive some of its statistical properties. We provide three special models which accommodate symmetrical, right-skewed and left-skewed shaped densities as well as bathtub, decreasing, increasing, reversed-J shaped and upside-down bathtub failure rate functions. The parameters are estimated by maximum likelihood, least squares and a percentile method. Some simulations investigate the accuracy of the three methods. We illustrate the utility of a special model through three applications to engineering field.

A smart bathtub system is a new type of accommodation with modern and intelligent facilities of a smart home automation system. It is equipped with a multi-sensor system that will be used to recognize human activities within the bathtub to make it secure, save energy and water. This system design with an interaction design process aims to enlarge product usability; was applied during the development tools. In this smart bathtub system, sensors have been installed with a variety of appliances, the presence sensor can be used to monitor human occupations, also the water level sensor to read the water level in the bathtub. Another part is the auto water faucet line that is supposed to flow water in the bathtub. The presence sensors detect a presence in the bathtub that would automatically initiate the automatic process. First, it detects the presence, and it checks the human activity in the bathtub while the system is active. If the object is present in the bathtub then the automation system will work otherwise not, like water level sensors and water faucet lines would not work if a person’s presence is not in the bathtub. Water level sensors send reading data to the microcontroller, if the water is empty water faucet will turn on, and water flows in the tub. The results demonstrate that the proposed method can detect the conditions of the bathtub presence activity and water level detect effectively with the best-experimented results showed 100% that the water line could be open if presence in the bathtub.

For the problem of how to keep water temperature constant and minimize water usage, this passage mainly discuss four parts to research. Consider that there exists thermal dissipation, and four types of thermal dissipation are heat conduction, thermal radiation, evaporative cooling and heat convection. The first step: discuss about the problem on condition of natural environment. There are two types of thermal dissipation of water in bathtub, one is by water contacting with air while another one is heat conduction of bathtub. Accumulate four types of thermal dissipation and then we obtain the relation of thermal dissipation with contacting area, initial water temperature in bathtub with stability of water in bathtub. Based on thermodynamic principle, we build three-dimensional partial differential equation of heat conduction from bathtub’s surface. Finally, we have the distribution graph of relation between temperature and time, space variation. The second type: Based on principle of Energy Conservation, we obtain the generalized partial differential equation of process of water dynamic variation with entering water’s temperature and outside temperature, and solve for problem that considering factors such as temperature variation with disturbance and bubble. The third step: Obtain the best designed model based on constant temperature, consider the minimum water usage and design length, volume and shape of the best designed bathtub. The fourth step: Use fuzzy PID algorithm to test and then obtain the convergence result. Proving that the built model is easy to adjust temperature and doesn’t possess big errors.

This paper proposes a novel identity validation method using ECG signal measured during bathing at 5 different bathtub water temperature ranges, that are 37 ±0.5 °C, 38±0.5 °C, 39±0.5 °C, 40±0.5 °C and 41±0.5 °C, respectively. The experiment includes 5 male and 5 female subjects, each subject collects 2 ECG recordings at each bathtub water temperature range, one day one recording, 10 ECG recordings are collected from each subject, each ECG recording is 18 minutes long, the sampling rate is 200 Hz. During the data processing stage, we perform spectrum analysis, baseline wandering removal, 50 Hz electromagnetic interference removal, signal smoothing, R peaks detection, and QRS complex segmentation. During the classification stage, we perform identity validation using long short-term memory (LSTM) classification network. 5 classification models are trained based on different bathtub water temperature ranges and the cross-validation method is used. Preliminary validation results show that different bathtub water temperature has an important impact on the identity validation. In order to precisely and quickly perform identity validation at different bathtub water temperature ranges, the final classification model is trained based on the samples from 5 different bathtub water temperature ranges. The highest and average identity validation accuracies are 98.43% and 97.68%, respectively.

In this paper, the discrete extended Weibull distribution is introduced by discretizing a new extended the continuous Weibull distribution. The new model has decreasing, increasing, constant and upside-down bathtub shaped hazard rates. Some of basic distributional and reliability properties are studied. The maximum likelihood method is used to estimate the parameters of the model. The performance of the estimation method is evaluated by a Monte-Carlo simulation. Four-real life data sets are considered for illustrating the advantages of the proposed distribution over some other well-known discrete distributions.

The advent of MLC/TLC/QLC and 3D/4D NAND flash memory technologies leads to increased capacity along with decreased reliability of SSDs. Flash storage is increasingly used in various fields such as mobile devices, internet of things (IoT) devices, home appliances, automobiles, etc. In such a system, the error handling techniques of the storage device have a great influence on the reliability of the system. Generally, failure rate of a storage device follows the bathtub curve. In particular, flash storage suffers from high bit error rate as flash memory undergoes P/E (Program/Erase) cycles. Though error rate of flash storage such as SSDs follows the bathtub curve, most of SSDs use the ECC scheme with fixed strength against failures. Hence, we propose Flexible Strength RAID (FS-RAID) scheme that employs RAID configuration and dynamically adjusts its strength against failures according to the typical failure rate of the device lifetime. In addition, we propose a method to greatly improve reliability by combining RAID parity and existing ECC. Through the evaluation using SSD simulator, we show that the proposed two techniques are quite effective.

Along with advances in medical technology and improvement in living standards, personal daily health management has got more and more attention. Bathtub electrocardiogram (ECG) has become an important index of personal daily health management. A study is conducted with one participant on a daily basis over one year. Bathtub ECG is measured during his daily bathing and used for heart rate variability (HRV) analysis. HRV stress index (SI) and optimal bathing time are calculated. The data of low SI and high SI are selected to analyze the effect of stress on the optimal bathing time. The results show that the optimal bathing time is delayed and it takes longer to achieve the comfort of bathing in the case of high SI.

This paper aims at exploring the variety of Electrocardiogram(ECG) interval and amplitude during different bathtub water temperature and eliminating their influence on personal identification with ECG. There are 10 subjects in the experiment, each subject collects 2 ECG recordings, each recording is at least 220 s. One recording is collected at 38±0.5 °C bathtub water temperature and the other recording is collected at 42±0.5 °C bathtub water temperature. All the raw ECG are removed baseline drift and normalized, then the R peaks are detected and all the R-R interval(RRI) and amplitude are calculated. Through statistical analysis method, we find that the median of RRI in low bathtub water temperature is bigger than in high bathtub water temperature for all subjects, and compared with low bathtub water temperature, the variety of R peaks amplitude has 3 situations in high bathtub water temperature: increase, decrease and unchanged. Then all the QRS complex are segmented and are taken as training data and test data. During the training stage, there are 3340 training datasets, 1670 training datasets are from low bathing water temperature and the other 1670 training datasets are from high bathing water temperature. In the testing stage, first we use 410 testing data which are from low bathtub water temperature to test the trained model, the best and robust identification rate is 87.07%, when we use the other 410 testing data which are from high bathtub water temperature to test the trained model, the best and robust identification rate is 87.32%. To the best of our knowledge, this is the first time to explore the variety of ECG interval and amplitude during different bathing water temperature. However, further improvements are still needed during different bathing environment.

An applicability of a remote (contactless) electrocardiogram (ECG) measurements in a bathtub is presented in the paper. Possibility of ECG measurements in shallowly filled tube with a water was examined. A bathing person was, both, sitting and lying during experiments performed. The problem became non-trivial when the bathing person was moving in reference to a fixed set of electrodes and located at the longer walls of the bathtub. However, the results obtained indicate that the sensitivity of a developed electrode array could enable such measurements. However, a spatial sensitivity distribution determines, both, the recorded ECG signal parameters and quality.

as India has been facing the consequences of drought, the development of efficient water and energy management revival schemes are inevitable for maintaining sustainability. Most is of our village infrastructure of our associated with over tanks and bathtub based on the population of village/street. Turn ON of public water tank pumps without considering tariff and time period (Peak and low peak), Turn OFF the pumps once the water overflows from the tank and Overconsumption of water for public water tubs are the hectic issues. Due to these issues, the excess amount of water is being wasted and a considerable amount of pressure is kept on the load dispatching center by adding load during the peak time period. In this paper, the embedded controller based revival scheme is proposed to suppress the wastage of water and improper energy utilization on a common interest. The real-time clock, GPRS module, and various sensors are interfaced with a controller to communicate with the pump and the operating personnel.

Ideally, the reliability can be assessed analytically, provided that an analytical solution exists and its presumptions are met. Otherwise, alternative approaches to the assessment must apply. This paper proposes a novel, simulation based approach that relies on stochastic timed automata. Based on the automata, our paper explains principles of creating reliability models for various scenarios. Our approach expects that a reliability model is then processed by a statistical model checking method, used to assess the reliability by statistical processing of simulation results over the model. Main goal of this paper is to show that instruments of stochastic timed automata and statistical model checking are capable of facilitating the assessment process even for adverse conditions such as bathtub shaped failure rates.

79GHz millimeter-wave radar has many advantages against image sensor, infrared sensor and microwave band radar. In this paper, we present a bathroom monitoring system using a 79GHz band sensor in order to prevent accidents caused by heat- shock and so on where a k-means clustering method is proposed to monitor the existence and motion of a bathing person. The measurement was conducted for various scenarios (normal bathing, falling, drowning, etc.) and the usefulness is discussed against waving from the surface of bathtub hot water. As a result, the estimated rate of the dangerous state is shown to be more than 90% for various bathing person’s movements in a bathroom.

This paper explores the impact of bathtub water temperature on personal identification with ECG signal using convolutional neural network. Ten volunteers' ECG records are collected with lead-III at low temperature of bathtub water $(38\pm0.2\ {{}^{\circ} \mathrm{C}}$ in average) and high temperature of bathtub water $(42\pm 0.5 {{}^{\circ}\mathrm{C}}$ in average) environments, respectively. Each record is about $5\pm 1$ minutes at low temperature and $4\pm1$ minutes at high temperature. In the data preprocessing stage, we denoise the original ECG signal and segment the QRS complex on a beat-by-beat basis. Then, we perform two interpolation calculations based on the QRS segmentation and convert the QRS complex into a binary image one by one. When we use the ECG signals which are collected at low temperature to train and test the CNN model, the identification rate is 82.67%. However, if we use the ECG signal collected at high temperature to test this trained CNN model, the identification rate is only 13.33%. Conversely, when we use the ECG signal collected at high temperature to train and test the CNN model, the identification rate is 85.50%. However, if we use the ECG signal collected at low temperature to test this trained CNN model, the identification rate is only 12.17%. Thus, we notice that the different bathtub water temperature has an important impact on the ECG signal patterns and it is feasible to perform personal identification by convolutional neural network with ECG signal collected during bathing at the same temperature.

This study proposes a warranty policy for repairable products with bathtub-shape failure rate. Based on bathtub-shape curve, the warranty period is divided into two stages. In the first stage, the failure rate is non-increasing. In the second stage, the failure rate is strictly increasing, and imperfect preventive maintenance actions are carried out periodically. All the failures occurring over the warranty period are restored by minimal repair. Two-fold Weibull competing risk model is used to describe the bathtub-shape curve. The warranty cost, which is fully paid by the manufacturer, is analyzed. A numerical optimization method is presented to achieve the optimal preventive maintenance strategy so as to minimize the warranty cost. A numerical example with actual failure data is provided to demonstrate the effectiveness of the proposed policy. The results show that the manufacturer can benefit from the proposed policy, and more cost will be saved if the minimal repair cost is higher.

As a part of risk assessment to the coastal inundation, the coastal inundation area was estimated by adopting a simple bathtub approach based on numerically obtained typhoon-induced surges from the model SLOSH (Sea, Lake, and overland Surges from Hurricanes) in southern coastal city of South Korea and digital elevation map (DEM) from National Geographic Information Institute of Ministry of Land, Infrastructure and Transport. The typhoon-induced surge heights were firstly computed while the historical typhoon MAEMI(2003) is approaching. The coastal inundation area is estimated by comparing the maximum envelop of waves (MEOW) and the elevation of land with zero-side rule (i.e. the simple bathtub approach). Comparing the inundation result to the observation data, their shapes of inundation are similar. This research mainly gained applicability of these estimating methods for estimating further potential coastal inundation.

Water is essential for everybody in earth. Unfortunately, in their dwelling, sometime people forgot to turn off the water tab, which makes water wasteful. When water flooding in a house, it can cause disturbance to the neighbors. At the same time, some place in the country, has limited water available. The objective of this study is to save water waste by developing saving water tool. It used detection water level to save water. This study proposes the development of saving water tool by using automatic device which open and close the water-tab to reduce water wastage. When the bath tub is full of water, smart home will decide to close the water-tap automatically. This study uses ultrasonic sensor to detect water level. When the sensor is reading the water surface and it closes to the ultrasonic sensor, a higher water will be indicatad, and before the flood happens the water-tap will be closed. This study uses Arduino Uno and fuzzy logic algorithm. Fuzzy logic approach was used to analyze the water level indication to make the water stops in the right time.

This paper presents a monitoring system with an ultrasensitive vibration sensor to detect heartbeat. The likelihood of fatal accident while bathing in Japan is higher than any other European country. The domestic accidents at bathroom have increased 1.7-fold over the past 10 years. Monitoring systems in a bathroom are therefore needed to prevent accidents that can't be foreseen. In this study, we utilized an innovative ultrasensitive vibration sensor that can detect micro vibration of heartbeat transmitted through a bathtub. We proposed a fuzzy echo state network to obtain heartbeat from the measured vibration data. In the experimental result, we discussed the effectiveness and applicability of the proposed method, comparing with an existing wearable heart rate monitor.

For the components of 1.5MW horizontal axis wind power gearbox, the reliability and failure rate of components of wind power gearbox are analyzed and calculated. The changing curve of dynamic reliability and failure rate with time are given. The variation rule of components about dynamic reliability and failure rate with time by the time-varying curves are also obtained. The analysis is conducted based on the dynamic reliability model of components under random loads. The analysis results show that the reliability is decreasing with time and the failure rate is also the same with the reliability. The failure curves have failure feature of earlier period for “Bathtub curves”. The results verify that the usability and practicability of mechanical components dynamic reliability mode. At the same time, it has guiding significance to determine the test time and reliable life of wind turbine gearbox components.

In this paper, a bathroom movements monitoring sensor system based on Ultra-Wideband Radio (UWB-IR) is suggested where a Cube Higher-order Local Auto-Correlation (CHLAC) method is employed to estimate some movements of a bathing person against waving from the surface of water in a bathtub. The usefulness of our suggested algorithm is investigated experimentally and it is shown that estimation rate of more than 90% can be attained for various a bathing persons movements in a bathroom.

A lifetime distribution model was proposed by Dimitrakopoulou, et al. in 2007 [1]. This model has three parameters and includes the Weibull distribution as a special case. Therefore, this is a Weibull related distribution model and it has decreasing, increasing, bathtub and upside-down bathtub-shaped failure rate. Since this distribution model has more flexibility than the conventional 2- and 3-parameter Weibull distributions in modeling the lifetime data, it is of interest to have a study on its statistical characteristics and explore the real application of the model to modeling time to failure data. The objective of this paper is to investigate the parameter estimation of this 3-parameter Weibull related model by graphical approach with short discussion on its statistical characteristics. The procedure in detail for parameter estimation of the model is presented and its usefulness is demonstrated by two real examples.

Most of the proposed age-reduction models was introduced and widely used in applications only for the case of monotonically increasing failure rates. However, from a practical perspective, there are several situations for which failure rates are decreasing or bathtub shaped. In these cases, the existing imperfect maintenance models may lead to the restoration of a system to the infant mortality period and can be considered as harmful. In this paper, we modify the usual assumptions on traditional age-reduction models to take into account the bathtub-shaped failure rates. Finally, we provide a numerical example to illustrate our result.

A method for developing a more systematic approach to determining the replacement time of transformers is presented. The approach is based on an economic analysis of transformers in conjunction with the technical issues involved in the decision process. Enhanced use is made of the well-known bathtub failure model, including repairs and scheduled maintenance, in order to arrive at a more economically oriented replacement decision. This goal is achieved in part by taking into account the uncertainty inherent in transformer failures and the corresponding interruptions in power. In essence, this technique constitutes a decision support system for determining the life expectancy of a transformer.

The bathtub curve is essential in interpreting the hazard rate or failure rate function for the engineering reliability analysis. An adaptive bathtub hazard function (ABF) or failure rate function curve modelling is proposed by using the transformed radial basis functions, which includes a type of symmetric ABF (SABF) and a type of asymmetric ABF (AABF). The ABF provides a parametric approach to represent the failure behaviours of various engineering applications and can also be easily utilised as the design objectives for the further accelerated life prediction, parameters determination and reliability based optimisation studies.

The power law process (PLP) and log linear process (LLP) are able to describe the processes with monotonic trend during the operating time. However, these models are not able to describe the processes with a non-monotonic trend such as bathtub shaped intensity. In this paper we proposed the superposed log linear process (S-LLP) for modeling bathtub shaped intensity function. The S-LLP is a nonhomogeneous Poisson process (NHPP) that results from the superposition of two LLP with different parameters. To get the maximum likelihood (ML) estimates, we proposed the three-parameter log-likelihood function evaluated using a genetic algorithm. Also, to obtain approximated confidence intervals, the information matrix and the variance-covariance matrix have been evaluated. The suggested methods are applied to field data from a repairable system.

This paper proposes a software reliability model with a ba thtub-shaped fault detection rate. We discuss how the inherent characteristics of the software testing process support the three phases of the bathtub; the first phase with a decreasing fault detection rate arises from the removal of simple, yet frequent faults like syntax errors and typos; the second phase possesses a constant fault detection rate marking the beginning of functional requirements testing; the third and final code comprehension stage exhibits an increasing fault detection rate because testers are now familiar with the system and can focus their attention on the outstanding and as yet untested portions of code. We also discuss how eliminating one of the testing phases gives rise to the burn-in model, which is a special case of the bathtub model. We compare the performance of the bathtub and burn-in models with the three classical software reliability models using the Predictive Mean Square Error and Akaike Information Criterion, by applying these models to a data set in the literature. Our results suggest that the bathtub model best describes the observed data and also most precisely predicts the future data points compared to the other popular software reliability models. The bathtub model can thus be used to provide accurate predictions during the testing process and guide optimal release time decisions.

This paper describes a new type of assistance system that can support bedridden patients to reduce the burden of nursing care. The first component is an electric wheelchair that can be modified to function as a portable bed by reclining the seat. The second component is a new type of lift for carrying a patient from the wheelchair to the bath, or to a normal bed. The third component is a new type of bathtub made from vinyl cloth and supported by an aluminum frame and that can be moved easily. Generally, it is difficult for a caregiver to move a bedridden patient between the bed and the bathroom, and bathing patients who are lying in bed is one of the most difficult tasks for caregivers. Using the proposed items such as the wheelchair and the lift, caregivers can more easily bathe patients. Another challenging task for caregivers is helping patients with incontinence. To help overcome this problem, we have designed a small mobile robot with a portable toilet to set up under the seat of the wheelchair. The robot can move inside the house after moving out from under the wheelchair. The proposed omni-directional mechanism allows the robot with the portable toilet to adjust not only to a narrow room such as a restroom but also to a narrow hallway. For the final component of our system, we designed a cleaning mechanism for the portable toilet, with an autonomous control system.

Daily monitoring of health condition at home is important for an effective scheme for early diagnosis, treatment and prevention of lifestyle-related diseases such as adiposis, diabetes and cardiovascular diseases. While a number of commercially available devices for home healthcare monitoring are widely used, those are actually cumbersome in terms of self-attachment of biological sensors and self-operation of them. From this viewpoint, we have been developing a non-conscious physiological monitoring system without attachment of any sensors to the human body as well as any operations for the measurement. We developed some devices installed in a toilet, a bath, and a bed and showed their high measurement precision by comparison with simultaneous recordings of ordinary biological sensors directly attached to the body. In order to investigate those applicability to the health condition monitoring, we developed a monitoring system in combination with all of the monitoring devices at hospital rooms and previously carried out the measurements of patients' health condition. Further in this study, the health conditions were measured in 10 patients with cardiovascular disease or sleep disorder. From these results, the patients' health conditions such as the body and excretion weight in the toilet, the ECG during taking the bath and the pulse and respiration rate during sleeping were successfully monitored in the hospital room, demonstrating its usefulness for monitoring the health condition of the subjects with cardiovascular disease or sleep disorder.

In this work, an active conbined carrier which combines a wheel chair and a bed is introduced. This carrier is designed for disabled or elderly persons by providing them with an integrated moving carrier and bath-bed, helping them use a bath without using their bodies. In particular, omni-directional wheels are utilized to move to any direction without turning the carrier body widely, reducing turing space and operation time. To be combined with the lying bathtub, the bed and wheel chair are separated by using distinguished mechanisms. At the same time, the carrier is designed to be docked with the bathtube autonomosly or manually. An appropriate wheel base is determined by taking weight balance and pulling force in a incline into consideration, which contributes to preventing turn-over in any case.

In the field of nursing care, caregivers have to bear a great burden due to assistive movements such as supporting of the care-receivers body, lifting them, moving them onto the wheel chair etc. In this paper, we focus on getting a care-receiver in and out of the bathtub, which is one of the most difficult movements for caregivers. Considering an important activity that puts a large burden on caregivers, lifting, there are many types of lifting devices available for transferring disabled people. Nevertheless it is difficult to use fixed equipment such as a mechanical lift with home care because it is expensive to rebuild the bathroom. The physical burden involved in assisting action in the field of nursing care can be greatly reduced by wearing the HAL (Hybrid Assistive Limb) full-body type. The objectives of this paper are to propose a new method of bathing care assistance using the robot suit HAL, to develop the upper half body of HAL, which reduces the physical burden on the wearer's upper limbs, and to show its effectiveness through an experiment. The study focused on reducing the trunk inclination angle, which is related to the physical load around the lumbar spine. The new method mainly uses the caregiver's upper limb to support the weight of the care-receiver. Therefore, we built a mechanism which locks the power unit of a HAL joint to assist the motor function of the wearer's upper limbs. To confirm the effectiveness of the proposed method, we demonstrated that the mechanisms of the power units kept the angles of the upper limbs steady while the wearer held a weight of 50(kg), and that the physical burden on the upper limb of the wearer was reduced. As a results of this experiment, we confirmed the effectiveness of the proposed method.

With the use of hardware software co-design and hardware software co-verification technology, test bench is introduced to test bathtub controller. Bathtub controller includes two parts: Touch Panel Controller (TPC) and Main Electronic Controller (MEC). The task of test bench is to test these two controllers. With the help of application-specific integrated circuit (ASIC), LCD, touch panel and dedicated software, testing work can be convenient and reliable.

For electronic products, the typical failure rate curve takes on three-stage bathtub shape, while few failure rate equations can describe the bathtub shaped curve. Based on environment load impact failure mechanism, the present paper develops load-property interference failure rate model for electronic products. The operation load, i.e. the impact is taken as a random process, and product property suffers degradation over service time. The ever changing load-property relationship yields the variation in failure rate curve. During service life, the product is continuously subjected to stochastic load impact, and product property degrades continuously. Since failure occurs when a load higher than the relevant property appears, failure rate model can be developed based on load statistical characteristic and product property. From such a principle, the variation in failure rate is interpreted in both the load uncertainty and product property uncertainty. Moreover, the effects of product property degradation, as well as load dispersion and product property dispersion on failure rate are highlighted.

Death due to drowning accounts for approximately 30% of unintentional injury deaths of 1- to 4-year-old children in Japan. Therefore, a drowning prevention system is strongly needed. This paper describes a newly developed system for preventing infant drowning accidents at home. The authors built a prototype system that does the following: measures the wave motion of water in a bathtub using a triaxial accelerometer, detects abnormal wave motion, and produces an audible warning to parents or guardians through radio communication. In this paper, the details of the system and the results of an experiment to collect data for abnormal wave motion detection are shown.

Death due to drowning accounts for about 30% of unintentional injuries of 1 to 4 year-old infants in Japan. A system for preventing infant drowning is strongly required. This paper describes a newly developed system for preventing infants 1G drowning injury at home. The prototype of infant drowning prevention system developed by the authors is presented. The developed system can measure the wave motion of water in the bathtub using a triaxial accelerometer, detect the abnormal wave motion, and give a warning to guardians with a radio communication. In this paper, the details of the system and the experimental results on abnormal wave motion detection are shown.

The bathtub curve is widely used in the reliability world to illustrate three characteristics of the system (or an IC) failure rate curve: the early failure rate during initial phase of life, the intrinsic random constant failure rate in the use life, and the wear-out phase at the end-of-life (Reddy, 2003). The bottom part is usually characterised by a constant failure rate expressed in FIT (failure in time, which is 1 failure in 109 device hours). As systems become more and more complex, more and more redundancy and EDAC (error detection and correction, also called error correction code ECC) are implemented in order to improve the system robustness and reliability (Slayman, 2003 and Ziegler and Puchner, 2004). By studying the data retention failure rates of Flash products with ECC, we found that the bottom part of the bathtub (used to be characterized by "random constant failure rate") is not flat. We suggest replace the FIT number by a cumulative failure fraction with a certain time stamp.

The ECG recording in the bathtub was studied using insulated electrode. Prior studies of the ECG recording in the bathtub used conductive electrodes having some problems such as the possibility of the electric shock and sensitivity to contamination of the electrode surfaces. The insulated electrodes were made of copper plate coated with PET film. The electrodes were attached on bathtub at both sides of the chest. High-input-impedance amplifier was designed to amplify ECG signal sensed by insulated electrodes of high impedance. The recorded signals in this study were noisier than those recorded with conventional conductive electrodes. But the R peaks in the recorded signals were large enough to be auto-detected. Further study will improve SNR by reducing of power line noise and common-mode noise.

Three automated monitoring systems used for home health care of 1) body and excreta weight in lavatory, 2) ECG in bathtub and 3) ECG in bed without utilizing body surface electrodes in a non-conscious manner at a pilot house called "Welfare Techno House" were designed. For the evaluation of these automated health monitoring systems, long continuous measurements of the health status in daily life of young and elderly subjects were carried out.

The possibility of attaching measurement systems to the bed and sanitary equipments in order to monitor physiological functions in daily life is examined. Preliminary experiments revealed that (1) information about body temperature and body movement during sleep can be obtained from temperature recordings in the bed, (2) electrocardiograms (ECGs) can be recorded in a bathtub through the tap water and (3) heart rate can be estimated by ECGs obtained on the toilet seat. >

In 1981 it was revealed that the instantaneous failure rate of a piece of electronic equipment decreases with age during its useful life and that the bathtub characteristic for hazard rate is an exception rather than the rule. The shape of the hazard rate curve for this device is studied by the authors. Investigators studying semiconducting device burn-in subscribe to the concept of freak failures which manifest themselves as a hump on the hazard rate curve. The authors call these curves the roller-coaster curves. It was postulated that aside from the long-term gross wear-out failures, all other failures develop from flaws. With some general assumptions on the flaw size distribution, one can show (by applying fatigue theory) that the flaws would emerge as failures that give a decreasing failure rate. >

A benchmark X-band AlGaAs-GaAs HBT MMIC power amplifier with 7 W output power, 14 dB gain and greater than 50% efficiency has been fabricated using a base-to-emitter re-aligned approach based on an electron-beam, direct-write technique. A novel flipside bathtub and metallization technology provides a practical means to reduce the thermal resistance of HBT cells and greatly enhance the microwave power performance. >

Rise and Shine is designed to assist its user in accessing a bed and bathtub by a means similar to a standard Hoyer Lift. The boom is raised and lowered by the user as well as turned on its axis. The user can also control the movement of the entire device, bringing the device with him to either the bedroom or bathroom.

Fully automated monitoring system of health status in daily life used at a pilot house called "Welfare Techno House (WTH)" was designed. This system was integrated with three monitoring devices of (1) body and excreta weight in lavatory, (2) electrocardiogram (ECG) in bathtub and (3) ECG in bed without utilizing body surface electrodes in a non-conscious manner at the WTH. For the evaluation of automated health monitoring system, the authors tried a long-term and continuous measurement to monitor health parameters on young and elderly subjects without disturbing ordinary daily life.