Professional Data Engineer 시험 - Google실제시험문제와 답 - 160문항

Question No : 1

How can you get a neural network to learn about relationships between categories in a categorical feature?

A.Create a multi-hot column
B.Create a one-hot column
C.Create a hash bucket
D.Create an embedding column

정답:
Explanation:
There are two problems with one-hot encoding. First, it has high dimensionality, meaning that instead of having just one value, like a continuous feature, it has many values, or dimensions. This makes computation more time-consuming, especially if a feature has a very large number of categories. The second problem is that it doesn’t encode any relationships between the categories. They are completely independent from each other, so the network has no way of knowing which ones are similar to each other.
Both of these problems can be solved by representing a categorical feature with an embedding column. The idea is that each category has a smaller vector with, let’s say, 5 values in it. But unlike a one-hot vector, the values are not usually 0. The values are weights, similar to the weights
that are used for basic features in a neural network. The difference is that each category has a set of weights (5 of them in this case).
You can think of each value in the embedding vector as a feature of the category. So, if two categories are very similar to each other, then their embedding vectors should be very similar too.
Reference: https://cloudacademy.com/google/introduction-to-google-cloud-machine-learningengine-course/a-wide-and-deep-model.html

Question No : 2

Which of these are examples of a value in a sparse vector? (Select 2 answers.)

A.[0, 5, 0, 0, 0, 0]
B.[0, 0, 0, 1, 0, 0, 1]
C.[0, 1]
D.[1, 0, 0, 0, 0, 0, 0]

정답:
Explanation:
Categorical features in linear models are typically translated into a sparse vector in which each possible value has a corresponding index or id. For example, if there are only three possible eye colors you can represent 'eye_color' as a length 3 vector: 'brown' would become [1, 0, 0], 'blue' would become [0, 1, 0] and 'green' would become [0, 0, 1]. These vectors are called "sparse" because they may be very long, with many zeros, when the set of possible values is very large (such as all English words).
[0, 0, 0, 1, 0, 0, 1] is not a sparse vector because it has two 1s in it. A sparse vector contains only a single 1.
[0, 5, 0, 0, 0, 0] is not a sparse vector because it has a 5 in it. Sparse vectors only contain 0s and 1s.
Reference: https://www.tensorflow.org/tutorials/linear#feature_columns_and_transformations

Question No : 3

What are two of the characteristics of using online prediction rather than batch prediction?

A.It is optimized to handle a high volume of data instances in a job and to run more complex models.
B.Predictions are returned in the response message.
C.Predictions are written to output files in a Cloud Storage location that you specify.
D.It is optimized to minimize the latency of serving predictions.

정답:
Explanation:
Online prediction
Optimized to minimize the latency of serving predictions.
Predictions returned in the response message.
Batch prediction
Optimized to handle a high volume of instances in a job and to run more complex models. Predictions written to output files in a Cloud Storage location that you specify.
Reference: https://cloud.google.com/ml-engine/docs/predictionoverview#online_prediction_versus_batch_prediction

Question No : 4

Suppose you have a dataset of images that are each labeled as to whether or not they contain a human face. To create a neural network that recognizes human faces in images using this labeled dataset, what approach would likely be the most effective?

A.Use K-means Clustering to detect faces in the pixels.
B.Use feature engineering to add features for eyes, noses, and mouths to the input data.
C.Use deep learning by creating a neural network with multiple hidden layers to automatically detect features of faces.
D.Build a neural network with an input layer of pixels, a hidden layer, and an output layer with two categories.

정답:
Explanation:
Traditional machine learning relies on shallow nets, composed of one input and one output layer, and at most one hidden layer in between. More than three layers (including input and output) qualifies as “deep” learning. So deep is a strictly defined, technical term that means more than one hidden layer.
In deep-learning networks, each layer of nodes trains on a distinct set of features based on the previous layer’s output. The further you advance into the neural net, the more complex the features your nodes can recognize, since they aggregate and recombine features from the previous layer. A neural network with only one hidden layer would be unable to automatically recognize high-level features of faces, such as eyes, because it wouldn't be able to "build" these features using previous hidden layers that detect low-level features, such as lines. Feature engineering is difficult to perform on raw image data. K-means Clustering is an unsupervised learning method used to categorize unlabeled data.
Reference: https://deeplearning4j.org/neuralnet-overview

Question No : 5

If you want to create a machine learning model that predicts the price of a particular stock based on its recent price history, what type of estimator should you use?

A.Unsupervised learning
B.Regressor
C.Classifier
D.Clustering estimator

정답:
Explanation:
Regression is the supervised learning task for modeling and predicting continuous, numeric variables. Examples include predicting real-estate prices, stock price movements, or student test scores.
Classification is the supervised learning task for modeling and predicting categorical variables. Examples include predicting employee churn, email spam, financial fraud, or student letter grades. Clustering is an unsupervised learning task for finding natural groupings of observations (i.e. clusters) based on the inherent structure within your dataset. Examples include customer segmentation, grouping similar items in e-commerce, and social network analysis.
Reference: https://elitedatascience.com/machine-learning-algorithms

Question No : 6

To run a TensorFlow training job on your own computer using Cloud Machine Learning Engine, what would your command start with?

A.gcloud ml-engine local train
B.gcloud ml-engine jobs submit training
C.gcloud ml-engine jobs submit training local
D.You can't run a TensorFlow program on your own computer using Cloud ML Engine .

정답:
Explanation:
gcloud ml-engine local train - run a Cloud ML Engine training job locally This command runs the specified module in an environment similar to that of a live Cloud ML Engine Training Job.
This is especially useful in the case of testing distributed models, as it allows you to validate that you are properly interacting with the Cloud ML Engine cluster configuration.
Reference: https://cloud.google.com/sdk/gcloud/reference/ml-engine/local/train

Question No : 7

Which of the following statements about the Wide & Deep Learning model are true? (Select 2 answers.)

A.The wide model is used for memorization, while the deep model is used for generalization.
B.A good use for the wide and deep model is a recommender system.
C.The wide model is used for generalization, while the deep model is used for memorization.
D.A good use for the wide and deep model is a small-scale linear regression problem.

정답:
Explanation:
Can we teach computers to learn like humans do, by combining the power of memorization and generalization? It's not an easy question to answer, but by jointly training a wide linear model (for memorization) alongside a deep neural network (for generalization), one can combine the strengths of both to bring us one step closer. At Google, we call it Wide & Deep Learning. It's useful for generic large-scale regression and classification problems with sparse inputs (categorical features with a large number of possible feature values), such as recommender systems, search, and ranking problems.
Reference: https://research.googleblog.com/2016/06/wide-deep-learning-better-together-with.html

Question No : 8

Which TensorFlow function can you use to configure a categorical column if you don't know all of the possible values for that column?

A.categorical_column_with_vocabulary_list
B.categorical_column_with_hash_bucket
C.categorical_column_with_unknown_values
D.sparse_column_with_keys

정답:
Explanation:
If you know the set of all possible feature values of a column and there are only a few of them, you can use categorical_column_with_vocabulary_list. Each key in the list will get assigned an auto-incremental ID starting from 0.
What if we don't know the set of possible values in advance? Not a problem. We can use categorical_column_with_hash_bucket instead.
What will happen is that each possible value in the feature column occupation will be hashed to an integer ID as we encounter them in training.
Reference: https://www.tensorflow.org/tutorials/wide

Question No : 9

Which software libraries are supported by Cloud Machine Learning Engine?

A.Theano and TensorFlow
B.Theano and Torch
C.TensorFlow
D.TensorFlow and Torch

정답:
Explanation:
Cloud ML Engine mainly does two things: Enables you to train machine learning models at scale by running TensorFlow training applications in the cloud. Hosts those trained models for you in the cloud so that you can use them to get predictions about new data.
Reference: https://cloud.google.com/ml-engine/docs/technical-overview#what_it_does

Question No : 10

The CUSTOM tier for Cloud Machine Learning Engine allows you to specify the number of which types of cluster nodes?

A.Workers
B.Masters, workers, and parameter servers
C.Workers and parameter servers
D.Parameter servers

정답:
Explanation:
The CUSTOM tier is not a set tier, but rather enables you to use your own cluster specification. When you use this tier, set values to configure your processing cluster according to these guidelines: You must set TrainingInput.masterType to specify the type of machine to use for your master node. You may set TrainingInput.workerCount to specify the number of workers to use. You may set TrainingInput.parameterServerCount to specify the number of parameter servers to use. You can specify the type of machine for the master node, but you can't specify more than one master node.
Reference: https://cloud.google.com/ml-engine/docs/trainingoverview#job_configuration_parameters

Question No : 11

Which of these numbers are adjusted by a neural network as it learns from a training dataset (select 2 answers)?

A.Weights
B.Biases
C.Continuous features
D.Input values

정답:
Explanation:
A neural network is a simple mechanism that’s implemented with basic math. The only difference between the traditional programming model and a neural network is that you let the computer determine the parameters (weights and bias) by learning from training datasets.
Reference: https://cloud.google.com/blog/big-data/2016/07/understanding-neural-networks-withtensorflow-playground

Question No : 12

Why do you need to split a machine learning dataset into training data and test data?

A.So you can try two different sets of features
B.To make sure your model is generalized for more than just the training data
C.To allow you to create unit tests in your code
D.So you can use one dataset for a wide model and one for a deep model

정답:
Explanation:
The flaw with evaluating a predictive model on training data is that it does not inform you on how well the model has generalized to new unseen data. A model that is selected for its accuracy on the training dataset rather than its accuracy on an unseen test dataset is very likely to have lower accuracy on an unseen test dataset. The reason is that the model is not as generalized. It has specialized to the structure in the training dataset. This is called overfitting.
Reference: https://machinelearningmastery.com/a-simple-intuition-for-overfitting/

Question No : 13

Which methods can be used to reduce the number of rows processed by BigQuery?

A.Splitting tables into multiple tables; putting data in partitions
B.Splitting tables into multiple tables; putting data in partitions; using the LIMIT clause
C.Putting data in partitions; using the LIMIT clause
D.Splitting tables into multiple tables; using the LIMIT clause

정답:
Explanation:
If you split a table into multiple tables (such as one table for each day), then you can limit your query to the data in specific tables (such as for particular days). A better method is to use a partitioned table, as long as your data can be separated by the day. If you use the LIMIT clause, BigQuery will still process the entire table.
Reference: https://cloud.google.com/bigquery/docs/partitioned-tables

Question No : 14

Which of these operations can you perform from the BigQuery Web UI?

A.Upload a file in SQL format.
B.Load data with nested and repeated fields.
C.Upload a 20 MB file.
D.Upload multiple files using a wildcard.

정답:
Explanation:
You can load data with nested and repeated fields using the Web UI. You cannot use the Web UI to:
Upload a file greater than 10 MB in size
Upload multiple files at the same time
Upload a file in SQL format
All three of the above operations can be performed using the "bq" command. Reference: https://cloud.google.com/bigquery/loading-data

Question No : 15

Which of these is not a supported method of putting data into a partitioned table?

A.If you have existing data in a separate file for each day, then create a partitioned table and upload each file into the appropriate partition.
B.Run a query to get the records for a specific day from an existing table and for the destination table, specify a partitioned table ending with the day in the format "$YYYYMMDD".
C.Create a partitioned table and stream new records to it every day.
D.Use ORDER BY to put a table's rows into chronological order and then change the table's type to "Partitioned".

정답:
Explanation:
You cannot change an existing table into a partitioned table. You must create a partitioned table from scratch. Then you can either stream data into it every day and the data will automatically be put in the right partition, or you can load data into a specific partition by using "$YYYYMMDD" at the end of the table name.
Reference: https://cloud.google.com/bigquery/docs/partitioned-tables

Google Professional Data Engineer 시험