Patent Publication Number: US-2022222520-A1

Title: Supervised vae for optimization of value function and generation of desired data

Description:
FIELD 
     The present invention relates to applications of Machine Learned and Artificial Intelligence models for use solving a problem of generating optimal samples for achieving a target outcome, and leverages a variational autoencoder (VAE) model to generate as realistic samples of a data space as possible. 
     BACKGROUND 
     In artificial intelligence (AI) applications, it is very common need to generate optimal data samples as inputs used to train machine learned models to achieve specific target outcomes. For example, a healthcare provider, e.g., a hospital, needs to optimize the utilization of their resources to achieve the best hospital performance. In this case, the resource utilization “real-world” input sample data is what would be needed to optimize on while the hospital performance is the target outcome. For another example, a teacher in a primary school needs to optimize an essay to show a 100-score model essay to his/her students. Here in this case, the real-world essay input data is what needs to optimized on, and the score is the target outcome. 
     However, there are several challenges when generating such desired input data samples. First, the relationship between the input data sample and the output target is not predefined and needs to be learned from a large dataset. In other words, a first challenge lies in that there needs to be modeled the relationship between input data x and the output data y. 
     Second, the space of input x is often high-dimensional and not clearly defined. In consequence, the straightforward optimization in space x is not feasible, and it is difficult to give explicit constraints on x. 
     Third, the generated optimal sample space corresponding to input x is required to be as similar as possible to the real-world samples. The generated samples should be sampled from the same distribution as the real-world data, in order to keep consistence with the real-world data. 
     Existing related methods cannot solve all of the above three challenges simultaneously. 
     SUMMARY 
     The following summary is merely intended to be exemplary. The summary is not intended to limit the scope of the claims. 
     According to an aspect, the present disclosure provides for a system and a method for generating optimal data samples for a machine learned model to achieve specific target outcomes when the relationship between the input sample and the output target is not predefined and needs to be learned from a large dataset, i.e., there needs to be modeled the relationship between an input data x and the output data y. 
     According to a further aspect, the present disclosure provides for a system and a method for generating optimal samples for specific target outcomes when the space of input data x is high-dimensional and not clearly defined such that any straightforward optimization in space x is not feasible, and rendered difficult to give explicit constraints on x. 
     According to a further aspect, the present disclosure provides for a system and a method for generating optimal samples for specific target outcomes such that the generated optimal sample x* are as similar as possible to the real-world samples, i.e., the generated samples should be sampled from the same distribution as the real-world data, in order to keep consistence with the real-world data. 
     According to an aspect of the present invention, there is provided a computer-implemented method of generating optimal model input data for achieving a target outcome. The method comprises: generating, using an encoder model of a supervised variational autoencoder (VAE), a latent feature representation of an input data in a latent feature space; receiving a VAE decoder model to learn to reconstruct the input data using the latent feature representation of the input data; receiving a value predictor model to learn a relationship between the input data and a target outcome using the latent feature representation of the input data; concurrently training the VAE decoder and value predictor models; optimizing, using the trained value predictor model, the latent feature space representation of the input data; receiving at the trained VAE decoder model, the optimized latent feature space representation of the input data, and running the trained VAE decoder model to generate optimal samples of the input data for achieving the target outcome based on the optimized latent feature space representation of the input data. 
     According to one aspect, there is provided a computer system for generating optimal model input data for achieving a target outcome. The computer system comprises: a memory storage device for storing a computer-readable program, and at least one processor adapted to run the computer-readable program to configure the at least one processor to: generate, using an encoder model of a supervised variational autoencoder (VAE), a latent feature representation of an input data in a latent feature space; receive a VAE decoder model to learn to reconstruct the input data using the latent feature representation of the input data; receive a value predictor model to learn a relationship between the input data and a target outcome using the latent feature representation of the input data; concurrently train the VAE decoder and value predictor models; optimize, using the trained value predictor model, the latent feature space representation of the input data; receive at the trained VAE decoder, the optimized latent feature space representation of the input data, and run the trained VAE decoder to generate optimal samples of the input data for achieving the target outcome based on the optimized latent feature space representation of the input data. 
     In a further aspect, there is provided a computer program product for performing operations. The computer program product includes a storage medium readable by a processing circuit and storing instructions run by the processing circuit for running a method. The method is the same as listed above. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing aspects and other features are explained in the following description, taken in connection with the accompanying drawings, wherein: 
         FIG. 1  schematically shows an exemplary computer system which is applicable to implement the embodiments for automatically generating optimal samples for specific target outcomes according to embodiments of the present invention; 
         FIG. 2  depict respective system block diagrams depicting a two-stage framework for generating optimal samples for specific target outcomes according to embodiments of the present invention; 
         FIG. 3  shows a method invoked by the computer system for running the two-stage framework for generating optimal samples for specific target outcomes according to an embodiment; 
         FIG. 4  depicts an example table indicating example optimal sample data input/outputs and optimized target outcome resulting from the two-stage network processing of an example resource utilization optimization problem according to embodiments of the present invention; 
         FIG. 5  illustrates a schematic of an example computer or processing system according to embodiments of the present invention; 
         FIG. 6  depicts a cloud computing environment according to an embodiment of the present invention; and 
         FIG. 7  depicts abstraction model layers according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     According to an embodiment, the present disclosure provides for a system and a method for rapidly and automatically generating optimal samples for a machine learned model to achieve a target outcome. A supervised variational autoencoder method is implemented to solve problems to generate optimal sample data which will bring an optimal target outcome (optimal value function). 
     In an embodiment, the system and method is implemented in two-stages: a learning stage and a generating stage. In the learning stage, a supervised variational autoencoder (VAE) is trained to learn both: (1) a distribution of an input data x; and (2) the relationship between the input data x and target output target y concurrently. In the generating stage, an unconstrained optimization problem is solved in the latent space z using an optimizer, to generate various data for different purposes. The system learns a value prediction function based on the latent feature instead of the original input data. The system provides a flexible data generation mechanism which is suitable for various kinds of target outcome specifications. 
     As shown in  FIG. 1 , in the context of solving problems to generate optimal sample data that will result in an optimal target outcome according to one embodiment, a tool  100  implementing systems and methods is a computer system, a computing device, a mobile device, or a server. In some aspects, computing device  100  may include, for example, personal computers, laptops, tablets, smart devices, smart phones, or any other similar computing device. 
     Computing system  100  includes one or more hardware processors  152 A,  152 B, a memory  150 , e.g., for storing an operating system, application program interfaces (APIs) and program instructions, a network interface  156 , a display device  158 , an input device  159 , and any other features common to a computing device. In some aspects, computing system  100  may, for example, be any computing device that is configured to communicate with one or more web-sites  125  including a web- or cloud-based server  120  over a public or private communications network  99 . For instance, a web-site may include input data relating to a particular domain. In an example implementation, such data may include hospital resource utilization data which may be used to solve a problem of how to minimize a labor expense of a hospital. Such data may be stored in electronic form in a database  130 . 
     Further, as shown as part of system  100 , there is provided a local memory useful for a data processing framework which may include an attached memory storage device  160 , or a remote memory storage device, e.g., a database, accessible via a remote network connection for input to the system  100 . 
     In the embodiment depicted in  FIG. 1 , processors  152 A,  152 B may include, for example, a microcontroller, Field Programmable Gate Array (FPGA), or any other processor that is configured to perform various operations. Additionally shown are the communication channels  140 , e.g., wired connections such as data bus lines, address bus lines, Input/Output (I/O) data lines, video bus, expansion busses, etc., for routing signals between the various components of system  100 . Processors  152 A,  152 B are configured to execute method instructions as described below. These instructions may be stored, for example, as programmed modules in a further associated memory storage device  150 . 
     Memory  150  may include, for example, non-transitory computer readable media in the form of volatile memory, such as random access memory (RAM) and/or cache memory or others. Memory  150  may include, for example, other removable/non-removable, volatile/non-volatile storage media. By way of non-limiting examples only, memory  150  may include a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. 
     Network interface  156  is configured to transmit and receive data or information to and from a web-site server  120 , e.g., via wired or wireless connections. For example, network interface  156  may utilize wireless technologies and communication protocols such as Bluetooth®, WIFI (e.g., 802.11a/b/g/n), cellular networks (e.g., CDMA, GSM, M2M, and 3G/4G/4G LTE, 5G), near-field communications systems, satellite communications, via a local area network (LAN), via a wide area network (WAN), or any other form of communication that allows computing device  100  to transmit information to or receive information from the server  120 . 
     Display  158  may include, for example, a computer monitor, television, smart television, a display screen integrated into a personal computing device such as, for example, laptops, smart phones, smart watches, virtual reality headsets, smart wearable devices, or any other mechanism for displaying information to a user. In some aspects, display  158  may include a liquid crystal display (LCD), an e-paper/e-ink display, an organic LED (OLED) display, or other similar display technologies. In some aspects, display  158  may be touch-sensitive and may also function as an input device. 
     Input device  159  may include, for example, a keyboard, a mouse, a touch-sensitive display, a keypad, a microphone, or other similar input devices or any other input devices that may be used alone or together to provide a user with the capability to interact with the computing device  100 . In an embodiment, through the user interface, the user can enter a specific target outcome intended for the problem to be solved. For example, in the context of solving a problem relating to hospital resource utilization, the user may specify a target outcome y such as how to minimize a labor expense of a hospital. 
     With respect to configuring the computer system to analyze and process data to generate an optimal sample (latent) space for building a model to generate a target output, the local or remote memory  160  may be configured for temporarily storing data or information  162  relating to the problem to be solved in the particular domain, e.g., hospital resource utilization data or other data obtained from a remote location, e.g., a web server(s). 
     These data is stored as a database and processed for use in generating the optimal sample space used to solve the problem at hand in a particular domain, e.g., healthcare, education, etc. 
     The captured data  162  can be data mined from information stored in the electronic databases  130  or other data sources (not shown). This data may alternately be stored in a separate local memory storage device attached to the computer system  100 . 
     As shown in  FIG. 1 , memory  150  of computer system  100  further stores processing modules that include programmed instructions run by the processor(s) adapted to configure the computer system to provide an optimal latent sample space for use in solving a problem using VAE techniques. 
     In one embodiment, one of the programmed processing modules stored at the associated memory  150  include a data ingestion module  165  that provide instructions and logic for operating circuitry to access/receive data (e.g., structured or unstructured) and rendering them in a form as input data x for use by other modules that process the data according to the embodiments of the invention. 
     In an embodiment, a VAE encoder module  170  provides instructions and logic for operating circuitry to receive input data content relating to the problem to be solved. This data may be an n-dimensional vector of information used for a prediction problem to be solved. The VAE encoder encodes the latent attributes of the input in a probabilistic manner (distribution) thereby generating a latent sample space. The encoder (E), captures the distribution of input data x and encodes input x into a disentangled latent space z. 
     In an embodiment, VAE encoder module  170  can run an encoding function modeled according to a deep neural network (DNN) model pipeline architectures, including but not limited to: Convolution Neural Network (CNN), Recurrent Neural Network (RNN) or Multilayer Perceptron (MLP) model pipelines, and possible combinations and variations thereof  175  that can perform the encoding of the input data x depending upon the type of problem being solved. 
     Another programmed processing module stored at the associated memory  150  of system  100  includes a VAE decoder module  180  employing logic and instructions for operating circuitry providing a decoder function to reconstruct the data x based on an input latent sample space z to within an optimal degree of error. In an embodiment, the decoder (D) module  180  can run a decoding function modeled according to a deep neural network model architecture, including but not limited to: CNN, RNN, or MLP model pipelines, and possible combinations and variations thereof  185  that can perform the decoding of the input latent sample space data z depending upon the type of problem being solved. 
     Another processing module stored at the associated computer memory  150  includes a value predictor module  190  employing logic and instructions for operating circuitry to run a function (V) for predicting a target outcome to within a specified accuracy. In an embodiment, the value predictor module  190  also runs a deep neural network model architecture, including but not limited to: CNN, RNN, or MLP model pipelines, and possible combinations and variations thereof that are configured to predict the value of a target outcome as precisely as possible, based on the latent features space z. 
     Another processing module stored at the associated computer memory  150  includes an optimizer module  195  employing logic and instructions for operating circuitry to solve a specific optimization problem. The optimizer runs optimization algorithm (O) to solve an unconstrained optimization problem for generating an optimized latent sample space z* for use in obtaining the best outcome for the target outcome specified in a prediction problem being solved. The optimization algorithm can be any common algorithm such as Stochastic Gradient Descent (SGD). Several types of optimizations can be performed, the only difference among them being the optimization target formulation. 
     As further shown in  FIG. 1 , memory  150  includes a supervisory program  110  having instructions for configuring the computing system  100  to call each of the program modules and invoke operations for supervised VAE learning and generating stages that optimizes a latent sample space z* for use in obtaining the best outcome for the target outcome specified in a prediction problem being solved, i.e., generate the most optimal samples having optimal target outcome. The supervisory program configures the computer system to generate the optimum target outcome values are represented as a data value x* obtained by decoding the optimal latent sample space z*, i.e., x*=D(z*). 
       FIG. 2  depicts a system implementing a two stage framework  200  for generating optimized latent variables z* in a latent variable space z as a result of processing input data x using a supervised VAE in a first stage, and an optimizer (O) in a second stage. 
     In a first learning stage  205 , input data x  210  in the form of one or more vectors including attributes relating to a particular problem to be solved is input to the encoder model (E)  175  of the supervised VAE. Based on the input attribute data vectors x, the encoder DNN model (E) is trained to capture the distribution of the input data x and by encoding input x into a disentangled latent variable space z, i.e., (E(x)→z. The encoder takes a sample data x as input, and then generates a feature representation z=E(x) in latent space  220 . Depending upon the input data type x, the embodiment of the encoder function (E) can be a CNN, RNN or MLP. The benefit of encoding is to transform the input in a complex high-dimensional space into a disentangled low-dimensional latent space  220 . 
     Continuing, as shown in  FIG. 2 , the decoder model  185  receives as input a sample latent space z  220  and decodes it to reconstruct the sample x, i.e., D(z)→x, to within some predetermined loss or error measure as determined by a loss function. Depending upon the input data type x, the embodiment of the decoder function (D) can be a CNN, RNN or MLP. As a result of the decoder model processing, the method generates the unsupervised reconstruction error loss |D(E(x))−x|. 
     Simultaneously, the value predictor model (V)  190  receives as input the same sample latent space z  220  and predicts the value of target outcome y  230  as precisely as possible, or to within a predetermined loss or error measure. Thus, besides learning the distribution of an input data x, using the latent variable space z  220 , the method also learns the relationship between input data x and a target outcome output y, i.e., x→z→(x, y), to within some predetermined loss or error measure as determined by a loss function. Depending upon the input data type x, the embodiment of the value predictor function (V) can be a CNN, RNN or MLP designed to model the relationship between the target outcome and the input data. However, it is not directly a function from x to y. It is a two-step function from x to z and then to y. This part generates the supervised prediction error loss |V(E(x))−y| for the training of VAE. Given these operations, the method can conduct downstream optimal sample generation for the target outcome. 
     During the training of the VAE model in the manner to predict an outcome given a sample latent space, the loss to be minimized is alternatively set forth according to equation 1) as follows: 
     
       
         
           
             
               
                 
                   
                     
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     where ∥D (E(x i ))−x i ∥ is the loss component representing a reconstruction loss of recreating the input data x, and ∥y i −V(E(x i ))∥ is the loss component representing a label prediction loss. 
     With more particularity, in the first learning stage  205 , the loss function of a supervised VAE is composed of three parts: 1) a reconstruction loss, i.e., E(log P(x|z)). This part can be further split into two parts for continuous features and discrete features; a 2) a prior loss, i.e., D_KL(Q(z|x)|P(z)). This part calculates the KL divergence distance between the posterior z|x and prior p(z); and 3) a prediction loss, i.e., E(log V(y|z)). In one embodiment, this part is the supervised loss which calculates the square error between y|z and true y. These loss functions can be customized according to specific application. That is, the method is an efficient solution to such a wide range of similar tasks, and different tasks may have different loss functions. 
     As further shown in  FIG. 2  depicting a system implementing a two stage framework  200  for generating optimized latent variables z* in a latent variable space z as a result of processing input data x using a supervised VAE in a first stage, the second learning stage  250 , runs an optimizing technique for solving an unconstrained optimization problem in the latent variable space z, and provides various data generation ways for different purposes. 
     In an embodiment, after the learning stage  205  is finished, in the generation stage  250 , the system runs optimizing module  195  to run an optimizer used to find optimal latent space variables z*  260  for a specific target outcome. 
     Depending upon the specific type of optimization problem solved, a different type of optimizer is used. The only difference among the optimizers is only the optimization target formulation. The optimization algorithm can be any common algorithm such as Stochastic Gradient Descent (SGD), Adam, AdaGrad. 
     In an embodiment, a first type of optimizer (O 1 ) solves a global optimization defined according to: 
         z *=arg max z   V ( z ). 
     where V(z) is the value predictor model. Using optimizer (O 1 ) the task is an unconstrained optimization to find the best sample which generates the largest target outcome value. 
     In a further embodiment, a second optimizer (O 2 ) solves a local optimization given a specific input data x that is defined according to: 
         z   x *=arg max Z   V ( z )−γ∥ d ( z )− x∥ 
 
     where V(z) is the value predictor function, D(z) is the decoder function applied to the corresponding latent space variable z, x is the specific input data value, and γ is a coefficient for controlling impact of the regularization term ∥D(z)−x∥. For example, the y coefficient for controlling impact of the regularization term can be 0.1, or 0.5 or other values. Using optimizer (O 2 ) the unconstrained optimization problem is tasked to generate optimal samples more like the given input x but with larger target outcome. 
     In a further embodiment, a third type of optimizer (O 3 ) solves a local optimization given a target outcome value y that is defined according to: 
         z   y *=arg min Z   ∥V ( z )−γ∥
 
     where V(z) is the value predictor function and γ is the predicted outcome value. Using optimizer (O 3 ) the task is an unconstrained optimization problem to generate optimal samples consistent with the target outcome value y. 
     As a result of solving the optimization problem using any optimizer (O 1 )−(O 3 ), for each latent space variable z there is generated a corresponding optimized latent variable space z*. 
     Continuing in  FIG. 2 , the optimized latent space variables z* are input to the supervised VAE decoder  180  to generate the optimized input data variable x*, i.e., D(z*)→x*, where x* is the final generated output sample. For example, given an input vector comprising variables x for a prediction problem to be solved, after running the first and second stages, there is generated a corresponding vector of optimized input variables x*, i.e., calculated to result in an optimized target outcome y. 
     That is, by subsequently inputting the optimized latent space input variables z* into the value predictor function V(z*), the predictor function will generate the most optimal (best) target output value y. 
       FIG. 3  shows a method implemented in the two-stage framework  200  of  FIG. 2 . At a first step  302 , the data ingestion module receives input data relating to problem to be solved and performs and any data formatting to render it in form for use by the VAE encoder module  170 . An example non-limiting problem to be solved is in the healthcare domain, particularly, a problem relating to optimizing resource utilization data x, e.g., in a manner so as to minimize labor expense cost per patient, a user-specified target outcome data y. The input data can include data from a number of hospitals, e.g., 100 hospitals. Each hospital provides input pairs of input data x and y. 
     For example, as shown in  FIG. 4 , given a healthcare provider such as a hospital, the hospital has some utilization of their resources, e.g., the number of beds, number of nurses, or some other resources. Different configurations of their resources would lead to different hospital performance. Thus, a problem to be solved would be how to optimize utilization of their resources so the hospital can obtain the best performance. 
     In an embodiment, the system  100  of the present invention is thus tasked to generate the optimal sample space with the best hospital resource utilization, which minimizes the labor expense of a hospital. 
       FIG. 4  shows a table  400  depicting the data input from each hospital including relevant resource utilization attributes data  402  (i.e., x is the real world data) that contribute to hospital expenses. In the example, received as input to the system is data relating to hospital resource usage at a number of hospitals, e.g., 100 hospitals. In an embodiment, the real-world input data  402  for each hospital is a data vector of 20 dimensions, each dimension corresponding to the hospital resource utilization attribute which is depicted as a respective row  401  as shown in the table of  FIG. 4 . Such data  402  from each hospital can include character type data  405 , e.g., binary data having values “1” or “0” indicating, for example, whether the hospital has 80% or more full time status employees, whether the patient has a case manager, whether the hospital is a teaching hospital, or does the nurse in charge provide clinical patient care 50% or more of the time, etc. Such data  402  from each hospital can include numeric type data  408 , e.g., number of overtime hours as a percentage of worked hours, an average wage index, a hospital case mix index value, a bed capacity, an equivalent average length of stay value, a value relating the hours paid per equivalent patient day, or a labor expense per equivalent patient day, etc. One of the hospital resource utilization attributes is shown at row  410  which corresponds to a target outcome value  420  intended to be optimized (minimized), i.e., labor expense per equivalent patient day. 
     In an embodiment, for each of the input data attribute values  402 , corresponding statistic values such as a median value  411  and mean value  413  are computed based on the input data from each hospital. For example, from each of the 100 hospitals&#39; input real-world data vector, there may be determined that the median “bed capacity” attribute  415  value is 24. The data from each hospital may be input as an m-dimensional vector, e.g., a 20-dimensional vector as shown in the hospital resource utilization example of  FIG. 4 . During the learning stage, the system learns the distribution of input data x. 
     Returning to  FIG. 3 , at step  302 , the user further specifies the target outcome y for problem to be solved. During the learning stage, the system learns the relationship between input data x and y. In the example of  FIG. 4 , the target outcome of the example problem is to optimize an attribute at row  410 , e.g., minimize the labor expense of a hospital. The method of  FIG. 3  of the example hospital resource utilization is thus to solve the problem of determining optimal samples x* which minimize the hospital labor expense (i.e., y* generated by the value predictor function V(z*)). 
     Continuing to  304 ,  FIG. 3  there is performed operations to run the VAE encoder module  170  function (E) on the received input data, e.g., the 20-dimensional data vectors from each hospital and to generate at  307  the latent sample space variables, a latent sample space z. Depending upon the task and input data type, encoder model function E( ) (and similarly D( ) and predictor V( ) functions) can be any one of MLP, CNN or RNN. For example, structural type of input data such as the 20-dimensional data vector in the hospital resource utilization example, is processed using a MLP model type encoder/decoder. 
     Alternatively, image type of input data will use a CNN model type encoder/decoder, where input data x is pixel data of a photograph and the target outcome y can be a score of the photo (e.g., beautifulness) of the photo. 
     Alternatively, time-series or sequential input data will use a RNN model type encoder/decoder. For example, in an education domain use case example, a teacher in a primary school needs to optimize an essay to show a 100-score model essay to his/her students. In such a use case, the essay is what is needed to optimize on, and the essay score is the target outcome (a 100 score essay). Given lots of essays data to capture, the relationship between the essay and a score, an optimal essay can be generated to give the 100 score. The input x* would be essays that product a 100 essay score. This would be different than a structural type data as the input data x is a sequence(s) of words and constitutes sequential data. 
     In an embodiment, such an encoder will reduce the dimensionality of the input sample x. For example, using a MLP model type encoder function, the output of the encoder processing transforms input dimensionality according to [20×5], i.e., reduces the 20-Dimensional data vector in the hospital example, to a 5-dimensional vector output. Using supervised training, an optimal encoder/decoder model is learned after conducting iterations as guided by minimizing the loss functions and tuning initial parameters to better reconstruct input x data and better predict target outcome value y. 
     Thus, at  310 , in concurrent operations, the latent sample space attributes z are input to the VAE decoder module function (D) which is run at  316  to obtain output reconstructed input samples x. At  310 , the latent sample space attributes z are concurrently input to a value predictor model (V) which is run at  316  to obtain output predictor value y. The decoder model can implement a [5×20] function to ensure the output dimension corresponds to the original input data x. The optimizing (e g, minimizing) of the loss function tunes the parameters in the encoder/decoder models. In the given example, the value predictor model (V) can implement a [5×1] function to ensure the output dimension corresponds to the desired target outcome y. 
     At  316 ,  FIG. 3 , using respective loss functions for the decoder and predictor models, respective error values are generated which are then evaluated at  318 . In an embodiment, the loss function of the supervised VAE is E(log P(x|z)) where E( ) is the expectation of log of the conditional probability P(x|z), i.e., the conditional probability of x i  given the latent variable z, as the autoencoder reconstructs an x as more likely to the input x. The P( ) function is defined using any particular probability distribution function, e.g., Gaussian distribution. If Gaussian distribution is used, this loss formula is transformed into the reconstruction loss function D(E(x i ))−x i  II to be minimized for recreating the input data x for each data attribute i according to equation 1). In an embodiment, this reconstruction loss can be split into two parts for continuous features and discrete features. 
     A further prior loss to minimize the dissimilarity between two probability distributions (Q and P) according to D_KL(Q(z|x)|P(z)) is computed. That is, a KL divergence loss function to measure the distance between the posterior z|x and prior p(z) is computed where Q(z|x) is the conditional distribution of latent variable z given input data x, and which corresponds to the decoder network and P(z) is the prior distribution of the latent variable z taken as following a simple distribution, e.g., standard Gaussian distribution. This prior loss term is minimized to avoid autoencoder overfitting of the input data x. 
     In an embodiment, the label prediction loss for each data attribute i is computed according to E(log V(y|z)) where V( ) is a probability distribution function and V(y|z) denotes the probability of y given z. This loss term is the supervised loss which calculates the square error between y|z and true y. It is desired to maximize the expectation of log V(y|z), i.e., E(log V(y|z)). Adopting a particular distribution in VO obtains the prediction loss ∥y−V(z)∥ or ∥y−V(E(x)∥) term of equation 1). 
     If at  318 ,  FIG. 3 , it is determined that the reconstruction loss and predictive label loss are not minimized, the process repeats by continuing to  320 ,  FIG. 3  in order to tune E( ), D( ) or V( ) model parameters and returning to  304 ,  FIG. 3  to again run the VAE encoder model, decoder model and predictor models to obtain respective latent space variables z, reconstructed input samples x and target predictor value y. Until the error loss is minimized without overfitting, steps  304  to  318  are repeated. 
     Once the error loss is minimized at  318  to within a specified accuracy, the process proceeds to  322  in order to use optimizer module  190  for optimizing the resulting latent sample space samples z* for the target outcome generated by the autoencoder, using optimization algorithm such as SGD, Adam, AdaGrad, etc. such that the samples z* are naturally similar to real-world samples. In particular, at  322 , an optimization objective whose maximum or minimum value is to be found is formulated. This optimization objective formulation is problem specific. for the example hospital resource utilization example shown in  FIG. 4 , the optimization objective is the labor expense attribute  420  represented as predictor function V(z), and an optimization problem is defined according to the first optimizer type as minV(z), i.e., the hospital labor expense attribute to be minimized. In this example, the optimal latent space variables z are denoted as z*=arg min V(z). Depending upon the specific problem, optimization objectives for an expected target outcome may be formulated using the other types of optimizers: z*=arg max z V(z) or z x *=arg max z V(z)−γ∥D(z)−x∥, or, if a specific target outcome y is provided, z y *=arg min z ∥V(z)−y∥. 
     In the hospital resource utilization example of  FIG. 4 , the expected target outcome y is the hospital labor expense  420 , which is the variable to be minimized according to z. That is, the optimization variables are the latent variable space. Thus, a first part of the optimization objective is about the variable y, and is solved using one of the three types of objective functions, e.g., z*=arg min V(z). 
     In an embodiment, for the optimal latent samples generating stage at  322 ,  FIG. 3 , the optimization objective is formulated according to equation 2) as follows: 
       min z   V ( z )−log  P ( z )  (2)
 
     where the first part  1 ) is the expected target outcome implementing one of the three optimizer types; and the second part  2 ) is a probability regularization term, i.e., the probability of the latent feature z*. This second regularization term ensures the high probability of the result z* and ensures the existence of the decoded sample, otherwise an extreme z* will lead to unrealistic sample x*. To regularize the variable z ensures that the probability of the result z* is not too small. 
     Finally, at  325 ,  FIG. 3 , the method generates the final optimal samples x* using z* to achieve target outcome y*. That is, decoder module  180  runs the VAE decoder model using the optimized latent sample space z* in order to generate the final optimal samples x* to achieve the target outcome. That is, at this step, to obtain x* the decoder function D( ) obtained from the learning stage is run as follows: 
         x*=D ( z *)= D (argmin  V ( z )) 
     The target outcome y* is obtained using the value predictor function V( ) obtained from the learning stage by computing: 
         y*=V ( E ( x *))= V ( z *)) 
     Returning to  FIG. 4 , for the hospital resource utilization example 400, the optimized target outcome y*  420  is a minimization of the hospital&#39;s labor expense which is the value 95.33. That is, after obtaining optimal resource utilization data x*, this vector is used to guide the changes at the 100 hospitals to decrease the labor expense and decrease cost. The vector of values in the denormalized data column  425  is the optimal samples x* that would achieve this target outcome. 
     As shown in the example table  400  of  FIG. 4 , as a result of running the methods herein to build an optimal latent sample space z*, the value predictor model will obtain an optimized target outcome output y* using the normalized optimal outcome data x*  423  and a corresponding de-normalized optimal outcome data x*  425 . The normalized outcome data x*  423  represents the deviation of the x* from the mean value of the input data, e.g., greater than the mean value (positive value) or less than (negative value). The de-normalized optimal outcome data x*  425  represents the best utilization values for each attribute (row) to accomplish the target outcome of minimizing the labor expense of a hospital. Thus, for a particular hospital, a best configuration of resource utilization shown in column  425  that would result in a minimizing of the labor expense of a hospital based on the original input data vectors x given for all 100 hospitals based on a target outcome of minimizing a labor expense or cost at that hospital. Based on the example 400 shown in  FIG. 4 , the mean value for the target attribute labor expense per equivalent patient day 420 for all 100 hospitals is $564.9. An optimal value for a hospital that minimizes the labor expense per equivalent patient day 420 is $95. The best resource utilizations at a hospital to achieve this optimal de-normalized value x* would be a configuration of hospital resources as shown at the column  425 . For example, using the example hospital resource utilization example, the x* vector provides a guidance to increase bed capacity attribute  415  from a mean value 24 to a new value 32 in achieving the desired outcome of decreasing labor expense. 
     The learning and generating framework  100  according to embodiments herein is that system comprehensively integrates four modules, including encoding, decoding, predicting, and optimizing and leverages the supervised VAE model to generate as realistic samples as possible. The system  100  learns a value prediction function based on the latent feature instead of the original input data, which is more robust. Further, the system solves the optimization problem in the latent space without constraints, avoiding the difficulty in optimizing in the original space x. The system  100  provides a flexible data generation mechanism which is suitable for various kinds of target outcome specifications. 
       FIG. 5  illustrates an example computing system in accordance with the present invention. It is to be understood that the computer system depicted is only one example of a suitable processing system and is not intended to suggest any limitation as to the scope of use or functionality of embodiments of the present invention. For example, the system shown may be operational with numerous other general-purpose or special-purpose computing system environments or configurations. Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with the system shown in  FIG. 5  may include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices, and the like. 
     In some embodiments, the computer system may be described in the general context of computer system executable instructions, embodied as program modules stored in memory  16 , being executed by the computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, and so on that perform particular tasks and/or implement particular input data and/or data types in accordance with the present invention (see e.g.,  FIG. 3 ). 
     The components of the computer system may include, but are not limited to, one or more processors or processing units  12 , a memory  16 , and a bus  14  that operably couples various system components, including memory  16  to processor  12 . In some embodiments, the processor  12  may execute one or more modules  11  that are loaded from memory  16 , where the program module(s) embody software (program instructions) that cause the processor to perform one or more method embodiments of the present invention. In some embodiments, module  11  may be programmed into the integrated circuits of the processor  12 , loaded from memory  16 , storage device  18 , network  24  and/or combinations thereof. 
     Bus  14  may represent one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnects (PCI) bus. 
     The computer system may include a variety of computer system readable media. Such media may be any available media that is accessible by computer system, and it may include both volatile and non-volatile media, removable and non-removable media. 
     Memory  16  (sometimes referred to as system memory) can include computer readable media in the form of volatile memory, such as random access memory (RAM), cache memory an/or other forms. Computer system may further include other removable/non-removable, volatile/non-volatile computer system storage media. By way of example only, storage system  18  can be provided for reading from and writing to a non-removable, non-volatile magnetic media (e.g., a “hard drive”). Although not shown, a magnetic disk drive for reading from and writing to a removable, non-volatile magnetic disk (e.g., a “floppy disk”), and an optical disk drive for reading from or writing to a removable, non-volatile optical disk such as a CD-ROM, DVD-ROM or other optical media can be provided. In such instances, each can be connected to bus  14  by one or more data media interfaces. 
     The computer system may also communicate with one or more external devices  26  such as a keyboard, a pointing device, a display  28 , etc.; one or more devices that enable a user to interact with the computer system; and/or any devices (e.g., network card, modem, etc.) that enable the computer system to communicate with one or more other computing devices. Such communication can occur via Input/Output (I/O) interfaces  20 . 
     Still yet, the computer system can communicate with one or more networks  24  such as a local area network (LAN), a general wide area network (WAN), and/or a public network (e.g., the Internet) via network adapter  22 . As depicted, network adapter  22  communicates with the other components of computer system via bus  14 . It should be understood that although not shown, other hardware and/or software components could be used in conjunction with the computer system. Examples include, but are not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc. 
     The present invention may be a system, a method, and/or a computer program product at any possible technical detail level of integration. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
     The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
     Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
     Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
     These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     The flowcharts and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The corresponding structures, materials, acts, and equivalents of all elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 
     It is to be understood that although this disclosure includes a detailed description on cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed. 
     Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models. 
     Characteristics are as follows: 
     On-demand self-service: a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with the service&#39;s provider. 
     Broad network access: capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs). 
     Resource pooling: the provider&#39;s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). 
     Rapid elasticity: capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time. 
     Measured service: cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service. 
     Service Models are as follows: 
     Software as a Service (SaaS): the capability provided to the consumer is to use the provider&#39;s applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based e-mail). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings. 
     Platform as a Service (PaaS): the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations. 
     Infrastructure as a Service (IaaS): the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls). 
     Deployment Models are as follows: 
     Private cloud: the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises. 
     Community cloud: the cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on-premises or off-premises. 
     Public cloud: the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services. 
     Hybrid cloud: the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds). 
     A cloud computing environment is service oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure that includes a network of interconnected nodes. 
     Referring now to  FIG. 6 , illustrative cloud computing environment  50  is depicted. As shown, cloud computing environment  50  includes one or more cloud computing nodes  11  with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone  54 A, desktop computer  54 B, laptop computer  54 C, and/or automobile computer system  54 N may communicate. Nodes  10  may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as Private, Community, Public, or Hybrid clouds as described hereinabove, or a combination thereof. This allows cloud computing environment  50  to offer infrastructure, platforms and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device. It is understood that the types of computing devices  54 A-N shown in  FIG. 6  are intended to be illustrative only and that computing nodes  10  and cloud computing environment  50  can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser). 
     Referring now to  FIG. 7 , a set of functional abstraction layers provided by cloud computing environment  50  ( FIG. 6 ) is shown. It should be understood in advance that the components, layers, and functions shown in  FIG. 7  are intended to be illustrative only and embodiments of the invention are not limited thereto. As depicted, the following layers and corresponding functions are provided: 
     Hardware and software layer  60  includes hardware and software components. Examples of hardware components include: mainframes  61 ; RISC (Reduced Instruction Set Computer) architecture based servers  62 ; servers  63 ; blade servers  64 ; storage devices  65 ; and networks and networking components  66 . In some embodiments, software components include network application server software  67  and database software  68 . 
     Virtualization layer  70  provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers  71 ; virtual storage  72 ; virtual networks  73 , including virtual private networks; virtual applications and operating systems  74 ; and virtual clients  75 . 
     In one example, management layer  80  may provide the functions described below. Resource provisioning  81  provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment. Metering and Pricing  82  provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may include application software licenses. Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources. User portal  83  provides access to the cloud computing environment for consumers and system administrators. Service level management  84  provides cloud computing resource allocation and management such that required service levels are met. Service Level Agreement (SLA) planning and fulfillment  85  provide pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA. 
     Workloads layer  90  provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include: mapping and navigation  91 ; software development and lifecycle management  92 ; virtual classroom education delivery  93 ; data analytics processing  94 ; transaction processing  95 ; and processing  96  to automatically generating optimal samples for a target outcome according to aspects of the present disclosure.