Wooden infant bed design under the background of two-child policy

Abstract

To cope with low fertility rate and an aging population, China introduced and implemented a two-child policy to make an overall population adjustment. Because of this, there are now problems, such as the uncoordinated sleep space for the two children, competition between older children, insufficient care for older children, and additional family affairs. In view of this, this study focused on the two-child family and parents as the main users of wooden infant beds. The method of constructing I-Kano model was used to determine the needs of users and their importance. Based on the QFD theory, the user needs and engineering measures were analyzed and explored. Based on the TRIZ theory, the analysis of engineering conflict resolution was performed. Based on the results, the wooden infant bed design strategy was developed for the background of two-child policy. The purpose of this work is to meet the parenting needs of two-child families in various periods with the developed design strategy, avoid the parenting problems of two-child families, improve the parenting quality of two-child families, adjust the sleeping space of two-child families, and fill the vacancy in the design theory of wooden baby beds for two-child families.

Full Article

Wooden Infant Bed Design under the Background of Two-child Policy

Xiaohang Du,^a,b Yi Wei,^a Fulin Zhang,^a and Zhaolong Zhu ^a,b,*

To cope with low fertility rate and an aging population, China introduced and implemented a two-child policy to make an overall population adjustment. Because of this, there are now problems, such as the uncoordinated sleep space for the two children, competition between older children, insufficient care for older children, and additional family affairs. In view of this, this study focused on the two-child family and parents as the main users of wooden infant beds. The method of constructing I-Kano model was used to determine the needs of users and their importance. Based on the QFD theory, the user needs and engineering measures were analyzed and explored. Based on the TRIZ theory, the analysis of engineering conflict resolution was performed. Based on the results, the wooden infant bed design strategy was developed for the background of two-child policy. The purpose of this work is to meet the parenting needs of two-child families in various periods with the developed design strategy, avoid the parenting problems of two-child families, improve the parenting quality of two-child families, adjust the sleeping space of two-child families, and fill the vacancy in the design theory of wooden baby beds for two-child families.

DOI: 10.15376/biores.19.3.6076-6094

Keywords: Two-child family; Wooden Infant bed; I-Kano model; QFD theory; TRIZ theory

Contact information: a: Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; b: College of Furnishings and Industrial Design, Nanjing Forestry University, Nanjing, Jiangsu Province, 210037, China;

* Corresponding author: njfuzzlong@outlook.com

INTRODUCTION

In order to cope with the low fertility rate and aging population, China officially launched the “universal two-child” policy on January 1, 2016 to make a population adjustment (Chen et al. 2019; Wu et al. 2019; Yang et al. 2022). Under the condition of continuously complete policy support and related supporting facilities, the number of second-child families is also increasing, and more parenting families are changing from the original only-child family structure to the family structure of multiple children (Xu et al. 2019; Meng and Lyu 2022). Due to the change of the structure of the parenting family, there are some new problems to be solved among family members (Hong and Liu 2021). There are problems, such as how to deal with the relationship between eldest children, second children, and the parents, and how to adjust the sleep space of the second child. However, at present, the design research of infant beds mainly focuses on the research of a single infant bed, and there are few design studies specifically for families with two children. In addition, the furniture research of second-child families mainly focuses on the home research of children, and less involving the furniture design of the infant stage of second-child families (Li et al. 2014; Salvador 2015; Liu et al. 2018). There is a vacancy in the design of infant beds in two-child families.

Compared to other materials, solid wood is advantageous as the primary material for infant beds in two-child families. It offers numerous benefits such as environmental friendliness and overall health. Meanwhile, solid wood provides excellent support and ensures a restful sleep for infants and young children. Moreover, high-quality wooden beds exhibit exceptional durability, allowing them to be used for an extended period of time (Gu and Zhang 2022). Additionally, solid wood possesses a natural aesthetic appeal that complements various decoration styles. Furthermore, its stable structure minimizes security risks effectively. From a production standpoint, solid wood materials facilitate a relatively simple manufacturing process while enabling the creation of diverse products. Consequently, solid wood is highly suitable for crafting infant beds in two-child families.

From the perspective of furniture design, the design of the product is divided into internal factors and external factors. Firstly, based on the method of I-Kano model analysis, the eldest child, second-child, and parents in the second-child family are centered, their core needs are analyzed, and the external factors of wooden infant bed design in the second-child family are determined (Lee et al. 2022). Then, according to QFD theory (Quality Function Deployment, QFD), external factors are transformed into internal factors of product design, and the contradictory relationship between engineering measures, the importance of engineering measures, and engineering measures are determined (Cristiano et al. 2001; Herzwurm et al. 2003; Kim et al. 2008; He et al. 2017). TRIZ theory (theory of inventive problem solving, TRIZ) was used to analyze and solve the contradiction engineering measures, and finally form a design strategy.

The purpose of this work is to meet the parenting needs of two-child families in various periods with design strategy, avoid the parenting problems of two-child families as much as possible, improve the parenting quality of two-child families, adjust the sleeping space of two-child families, and fill the vacancy in the design theory of wooden baby beds for two-child families.

I-KANO MODEL ANALYSIS DETERMINES USER CORE REQUIREMENTS

Based on user interviews, the living conditions and needs of the second-child parenting families were determined. A total of 10 representative families with two children were selected for interviews. From the respondents’ family situations and events, the living conditions of second-child families, as well as the use and needs of cribs, were learned. Then, the I-Kano questionnaire was distributed, and the I-Kano model was used to analyze the attributes and importance of various user needs.

Requirements Collection and Summary

First, the needs of wooden infant bed users were summarized. The demand for wooden baby beds in second-child families is divided into two levels, namely, the first level demand and the second level demand. Among them, the first-level demand is the demand for five aspects of the second-child family wooden infant bed design, including growth demand, security demand, humanized demand, intelligent demand, and emotional demand. Secondary requirements are detailed requirements for various aspects, as shown in Table 1.

Table 1. Summary of User Requirements

Demand Questionnaire Survey

Due to the limited number of interviewed users, surveys need to be conducted on a larger scale with the I-Kano model questionnaire and determine the core needs.

According to the requirements of the Kano model questionnaire survey, two positive and negative questions are set for each demand, and the needs of users are studied (Xu et al. 2007; He et al. 2017; Koomsap et al. 2023). The questionnaire is then sent by the Internet. After excluding the invalid questionnaires, 173 valid questionnaires were collected.

Core Requirements Screening

According to the I-Kano model calculation, the user demand data was summarized, and the user demand analysis table (Table 2) from the I-Kano model was obtained.

Because this user demand is not obtained with traditional brainstorming and other methods, but based on user interviews, the requirements for participating in the I-Kano model research are all proposed and needed by real users. That is to say, all of the above needs are not differentiated in the traditional sense but divide the investigated needs into core needs and non-core needs. In the I-Kano model user requirements analysis table, ‾X_i the value with‾Y_i all the values are positive, indicating that there is no requirement for reverse attributes and problem attributes in the survey. To screen out the core requirements of wooden infant beds, the importance index (R_i) and the satisfaction index (α_i) were introduced. The importance index (R_i) indicates the importance of the requirement. The satisfaction index (α_i) represents the relative level of satisfaction or dissatisfaction of the user after the requirement is met. One selects the importance index R₀ = 0.850, which is used as the critical value. User needs are divided into core needs and non-core needs, select α_L = 0.785 as the critical value below the satisfaction index. Also, the researcher selects α_H = 0.873 as the critical value above the satisfaction index.

Table 2. User Requirements Analysis Table of the I-Kano Model

Eventually, adjustments are made so that the two children’s sleep space, convenient diaper changing, suitable for different stages, interesting appearance, extended service cycle, and collision are the essential attributes in the core requirements; entertainment function, easy to splice with large bed, intelligent sleep, convenient for parents to observe and take care of children in the big bed, and reasonable storage were determined as the expected attribute requirements in the core requirements; it covers a small area was identified as the charm attribute in the core requirements; other requirements were identified as non-core requirements.

Although the attributes of user needs have been determined, the importance of demand cannot be determined solely by the division of demand attributes, and the importance of demand is the result of the joint action of many aspects. Therefore, the user demand priority index (p_i) is introduced (Jie et al. 2009). Priority index (p_i) is used to represent the comprehensive value of each user demand in meeting customer expectations, and as a basis for prioritizing which user needs are met. Based on the comprehensive analysis of the importance index and satisfaction index, the value of each user demand priority index is obtained, and the importance of demand is ranked according to its value from large to small. The specific ranking is shown in Table 2 and p_i is calculated as below (Jie et al. 2009):

(1)

QFD THEORETICAL ANALYSIS DETERMINES THE ENGINEERING MEASURES

Using the quality house analysis method in QFD theory, the needs of users are transformed into the corresponding engineering measures, according to the importance of each engineering measures, to determine the core engineering measures. Then, the contradictory relationship between the engineering measures is analyzed, and the mutual hindering engineering measures are determined.

Determine the Demand Importance

According to the above analysis, the importance of the user’s core needs is obtained. However, the importance range of the I-Kano model is (0≤ p_i ≤ 1.333).

Table 3. Importance of Quality House User Requirements

In this study, the maximum user demand of I-Kano model is 0.648. This does not match the value range of user demand importance (0 ≤ k_i ≤ 5) in the House of Quality. Therefore, the adjustment coefficient I = 7.716 is introduced.

(2)

The priority index in the I-Kano model is connected with the importance of user demand in the quality house, and the final results are shown in the importance of user demand in the quality house in Table 3.

Determination of Engineering Measures

Based on the analysis of the core needs of the users, the engineering measures to meet the corresponding needs were determined, as shown in Table 4.

In terms of safety requirements, preventing infant and child bumps has been identified as a core requirement. The bump mainly occurs in the prominent corner position, so the two engineering measures are put forward. An increase of the chamfer radius of the corner and fence and other frames can be implemented to increase the contact area and reduce the damage to infants and children. Additionally, a cushion is padded at the position of the corners to soften it. Based on these measures, one can avoid incidents in two-child families in the process of child care accidental injury.

In terms of growth needs, different periods suitable for infants and young children and extended use periods were identified as core needs. As the child grows up, the size of the original crib cannot meet the needs of the child’s sleep space, and its size needs to be expanded to have more space. When the needs and state of the children are different, the wooden baby bed needs to carry out the corresponding changes. When the child grows up and sleeps separately from his parents, the traditional crib loses its use and is no longer needed, and the use cycle is over. This causes a certain amount of waste. It can continue to be used by second-child families by making it have other furniture functions to meet the needs of extending its use cycle. Alternatively, it can be given or sold to another family that needs it. With these measures, the crib can be adapted to the various parenting situations of two growing children and can be used as the children grow up.

In terms of humanized needs, adjusting the sleep space of two children, convenient diaper change, covering a small area, convenient splicing with the big bed, reasonable storage, and convenient for parents to observe and take care of children in the big bed were identified as the core needs. In terms of regulating the sleeping space for two children, it is crucial to provide appropriate and adequate sleeping arrangements. When designing wooden infant beds for families with two children, more emphasis should be placed on adjusting the sleeping space compared to those designed for single-child families. Firstly, it is essential to meet the varying sleeping space requirements of two children at different stages of growth simultaneously. For instance, an infant as a second child would require a smaller sleeping area, while an older child would need a bed size similar to that of an adult. This example represents only one possible combination in families with two children; therefore, this study will further analyze various potential combinations that may arise during the parenting process in such families. Additionally, optimizing limited bedroom space utilization and facilitating seamless transitions between different combinations are also important considerations. The traditional wooden infant bed height is too low, and parents need to bend down as much as possible to change their children’s diapers, which is prone to cause waist and back pain. A care desk needs to be set up to address this pain point. Another problem is that the operation space of the traditional wooden baby bed is too small, parents in the diaper change action are often blocked by the fence, and the temporary storage of new diapers, new bedding, and other items also lack suitable storage space. It covers a small area, mainly considering the limited space of the parents’ bedroom, and an excessively large baby bed is difficult to place in the parents’ bedroom space or would seriously hinder the daily life actions. For this reason, a smaller baby bed size and more compact function module are used to reduce the footprint. In terms of convenience and large bed splicing needs, measures that can adjust the height of wooden infant beds are needed to adapt to the height of large beds in different families. In terms of storage requirements, in order to store children’s toys, diapers and other daily items, larger storage space and reasonable storage methods are needed to make the storage area more reasonable. For the measure of making it convenient for parents to observe and take care of their children when resting in the big bed, it is mainly to deal with the situation of child care when parents sleep at night. At this time, if the wooden baby bed is fenced, it will bring inconvenience to parents to observe and care for the children. Therefore, to reduce the sight blocking in the crib, removable barrier measures become an important measure to meet this need. Based on these measures, the common problems in the parenting process and the unique problems, such as two children competing for sleeping space in two-child parenting families have been solved.

Table 4. Engineering Measures to Meet the Requirements

In terms of intelligence, intelligent sleep coaxing has been identified as a core need of second-child parenting families. According to the study, for the other conditions of parenting families, the way to sleep is mainly the use of sound to induce sleep and shaking to encourage sleep. For these two methods, two engineering measures of the shaking sleep coax module and the music playback module are used to meet the needs of intelligent sleep coax (Möller et al. 2019).

In terms of emotional needs, fun appearance and entertainment are identified as core needs. Interesting appearance demand needs to pay attention to the design of color, modeling, and the use of cartoon elements. The entertainment aspect can be satisfied via music entertainment and upper hanging toys. These measures can be used to meet the emotional needs of parents and children in parenting families.

Build the Relationship Matrix between Requirements and Engineering Measures

After communication with relevant experts in the industry, the close relationship between the user’s core needs and engineering measures is analyzed, and the relationship matrix between user needs and engineering measures is summarized and drawn. The closeness of user requirements and engineering measures (r_ij) adopts the scoring method of 0, 1, 3, and 5 points:

0- There is no correlation between user needs and engineering measures;

1- There is a weak relationship between user demand and engineering measures;

3- There is a close relationship between user demand and engineering measures;

5- There is a very close relationship between user needs and engineering measures.

The corresponding score is represented by the specific symbol when the matrix is plotted to facilitate the observed analysis of the matrix: △ represents 1, ○ represents 3; ◉ represents 5, blank represents 0.

The relationship matrix analysis between specific user needs and engineering measures is reflected in the data of the room part of the wooden infant bed quality house under the background of the two-child policy in Fig. 7.

Determine the Importance of Engineering Measures

The relationship matrix between user requirements and engineering measures is analyzed by calculating the importance of engineering measures (h_j). The importance of engineering measures is determined by the value of engineering measures (hj). The larger the value, the more important the engineering measure. (Lyu et al. 2022).

According to the formula, the importance of each engineering measure is obtained, which is summarized and sorted according to the importance of engineering measure from the largest to the smallest, and the summary table of the importance of engineering measure is made in Table 5. In addition, the average of the importance of engineering measures is 54.203, and the average of 1.25 times is 67.254. Generally, engineering measures whose importance is higher than the average of 1.25 times of all engineering measures are taken as the control focus. Therefore, the guardrail can be removed, the shape can be changed according to the demand, the sleep space is reasonable, the height of the bed surface can be adjusted, the length changes with the growth of children, and the space volume is appropriately determined as the key engineering measures.

Table 5. Summary of the Importance of Engineering Measures

Construct the Engineering Measures Correlation Matrix

There may be some interactions between the engineering measures. Some interactions will have positive effects on other engineering measures, namely, a positive correlation, with the “+” symbol in this study, and some will have a negative effect, namely, a negative correlation, with the “-” symbol in this study. If the correlation between each of the two engineering measures is not strong, it is left blank. After the analysis of the interaction between various engineering measures, the correlation matrix of engineering measures is finally summarized and formed. See Table 7 for the roof part of the wooden infant bed quality under the background of the two-child policy.

With the analysis of the correlation of engineering measures, it is found that the engineering measures that offset and hinder each other are divided into two aspects. They are space problems and shaking to sleep. The negative related engineering measures are summarized in Table 6.

Based on the above analysis, it is found that the shaking module is mainly used to meet the needs of intelligent sleep, and the music playback function module is also closely related to the needs of intelligent sleep, and music sleep can also meet the needs of intelligent sleep. Shake the functional module is the least important in the analysis of the importance of the engineering measures. In addition, the shaking module conflicts with a number of engineering measures, deciding that the design of the wooden baby bed in the second child family is to abandon the shaking function module, and the music playback module replaces it to meet the demand of intelligent sleep.

Table 6. Negative-related Engineering Measures Table

Table 7. Wooden Baby Bed Quality House under the Background of the Two-Child Policy